Free Online Tools
for Everyone

File & Data

JSON to CSV / Excel Converter

Convert a JSON array to a downloadable CSV or Excel file instantly. Client-side only — your data never leaves your browser.

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File & Data

JSON Formatter & Validator

Format, validate, and minify JSON instantly. Inline error messages show exactly where your JSON is broken.

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File & Data

CSV to JSON Converter

Parse a CSV file or paste comma-separated data and get a clean JSON array. Supports custom delimiters.

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File & Data

CSV ↔ TSV Converter

Convert between comma-separated (CSV) and tab-separated (TSV) formats. Handles quoted fields correctly.

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File & Data

XML ↔ JSON Converter

Convert XML documents to JSON objects and JSON back to XML. Uses the browser's native XML parser.

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File & Data

YAML ↔ JSON Converter

Convert YAML to JSON and JSON to YAML instantly. Supports YAML 1.2, anchors, and multi-document files.

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File & Data

Base64 Encoder / Decoder

Encode text or files to Base64 and decode Base64 strings back to the original. Full Unicode support.

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File & Data

Markdown Previewer

Write Markdown on the left and see a live HTML preview on the right. Copy the rendered HTML with one click.

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File & Data

File Size Converter

Convert between bytes, KB, MB, GB, TB, and PB in both binary (1024) and decimal (1000) systems.

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File & Data

HTML → Markdown Converter

Paste any HTML block or web page source and get clean Markdown instantly. Handles headings, links, lists, bold, italic, and code.

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File & Data

JSON Comparator

Paste two JSON objects side by side and instantly highlight added, removed, and changed keys.

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File & Data

TOML ↔ JSON Converter

Convert TOML configuration files to JSON and back. Supports all TOML v1.0 data types.

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File & Data

Email Header Parser

Paste raw email headers and instantly visualise the SMTP routing path, timestamps, spam scores, and key fields.

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Developer Tools

Color Converter & Picker

Convert colors between HEX, RGB, HSL, and OKLCH. Includes a visual color picker.

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Developer Tools

Hash Generator

Generate SHA-1, SHA-256, and SHA-512 cryptographic hashes from any text string.

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Developer Tools

UUID / ULID Generator

Generate RFC 4122 UUID v4 identifiers and ULIDs in bulk. Copy one or all at once.

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Developer Tools

Regex Tester

Test regular expressions live against custom input. Highlights matches and displays capture groups.

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Developer Tools

JWT Decoder

Decode and inspect JWT tokens client-side. Reads the header, payload, and expiry without sending data anywhere.

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Developer Tools

URL Encoder / Decoder

Encode and decode URL components and full URLs. Supports both encodeURI and encodeURIComponent modes.

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Developer Tools

Cron Expression Explainer

Parse any cron expression and get a plain-English explanation plus the next 5 scheduled run times.

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Developer Tools

Password Generator

Generate strong random passwords with configurable length and character sets. Live strength meter included.

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Developer Tools

Timestamp Converter

Convert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds.

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Developer Tools

Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal instantly.

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Developer Tools

QR Code Generator

Generate a QR code from any URL or text. Download as PNG instantly.

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Developer Tools

CSS Gradient Generator

Build linear and radial CSS gradients visually. Live preview and copy-ready CSS output.

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Developer Tools

Lorem Ipsum Generator

Generate Lorem Ipsum placeholder text by word count, sentence count, or paragraph count.

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Developer Tools

CSS Specificity Calculator

Enter any CSS selector and instantly get its specificity score (a, b, c). Compare two selectors to see which wins.

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Developer Tools

HTTP Status Code Reference

Look up any HTTP status code: meaning, use cases, and whether it is cacheable. Covers all 1xx–5xx codes.

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Developer Tools

.htaccess Generator

Build an Apache .htaccess file with checkboxes: HTTPS redirect, www/non-www, custom 404, cache rules, CORS, and more.

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Developer Tools

DNS Lookup

Query A, AAAA, MX, TXT, CNAME, NS, and SOA records for any domain using Cloudflare DNS-over-HTTPS. No server needed.

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Developer Tools

IP Address Info

Detect your public IP address and look up geolocation, ISP, and ASN for any IP using a public API.

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Text Tools

Word & Character Counter

Count words, characters, sentences, and paragraphs in real time. Estimated reading time included.

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Text Tools

Text Case Converter

Convert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, and kebab-case instantly.

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Text Tools

Text Diff Checker

Compare two texts side-by-side and highlight added, removed, and unchanged lines.

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Text Tools

Line Sorter & Deduplicator

Sort lines alphabetically, reverse, shuffle, or remove duplicates from any block of text.

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Text Tools

Slug Generator

Convert any title or phrase into a clean URL slug. Handles accents, special characters, and multiple separators.

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Text Tools

Text Reverser & Palindrome Checker

Reverse text character by character or word by word, and check if a phrase is a palindrome.

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Text Tools

Morse Code Translator

Encode text to Morse code and decode Morse code back to text. Supports letters, digits, and punctuation.

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Text Tools

ASCII Art Generator

Convert any text into large ASCII art block letters for use in code comments, READMEs, and banners.

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Text Tools

Word Frequency Counter

Paste any text and get a sorted word frequency table — great for writing analysis.

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Text Tools

Find & Replace

Bulk find and replace text with optional regex support, flags, and match highlighting.

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Text Tools

Readability Analyzer

Paste any text and get Flesch-Kincaid Grade, Flesch Reading Ease, and Gunning Fog scores with school-level interpretation.

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Text Tools

Typographic Cleaner

Fix common typographic mistakes: replace straight quotes with curly quotes, hyphens with em/en dashes, and normalize spaces.

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Text Tools

Number to Words Converter

Convert any integer into its written English or French equivalent. Useful for cheques, contracts, and legal documents.

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Text Tools

Email Subject Line Analyzer

Analyse your email subject line: character count, spam trigger words, mobile preview, and deliverability tips.

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Image Tools

Image Resizer

Resize images to exact pixel dimensions or by percentage. Preserves aspect ratio. No upload to any server.

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Image Tools

Image Compressor

Reduce image file size with a quality slider. Compare original and compressed sizes before downloading.

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Image Tools

Image Format Converter

Convert images between PNG, JPEG, and WebP formats instantly in your browser.

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Image Tools

Image Cropper

Crop images to custom dimensions by entering coordinates or dragging the crop region.

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Image Tools

Image to Base64

Convert any image to a Base64-encoded data URI for use in HTML, CSS, or JSON.

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Image Tools

Favicon Generator

Upload an image and download optimized favicons at 16×16, 32×32, 48×48, and 180×180 px.

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Image Tools

SVG Optimizer

Clean and minify SVG files by removing comments, metadata, and unnecessary whitespace.

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Image Tools

Color Palette Extractor

Upload an image and extract its dominant colors as HEX, RGB, and HSL values.

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Image Tools

EXIF Metadata Viewer

Drop any JPEG or TIFF image and read its EXIF metadata: camera model, GPS coordinates, exposure settings, and more.

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Image Tools

Image Color Picker

Drop an image, hover to preview colors, click any pixel to get its HEX, RGB, and HSL values instantly.

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Image Tools

Image Diff

Compare two images side by side. Pixel-level difference highlighting shows exactly what changed between versions.

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Office & Productivity

Unit Converter

Convert between units of length, weight, volume, temperature, area, and speed instantly.

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Office & Productivity

Scientific Calculator

Full-featured scientific calculator with trigonometry, logarithms, and full keyboard support.

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Office & Productivity

Date Difference Calculator

Find the exact number of days, weeks, months, and years between any two dates.

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Office & Productivity

Percentage Calculator

Calculate percentages, percentage change, tip amounts, and discounts in seconds.

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Office & Productivity

BMI Calculator

Calculate your Body Mass Index (BMI) from height and weight in metric or imperial units.

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Office & Productivity

Pomodoro Timer

Focus timer based on the Pomodoro Technique: 25-minute work sessions followed by short and long breaks.

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Office & Productivity

Quick Checklist

A simple, fast checklist that saves automatically in your browser. No account needed.

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Office & Productivity

Invoice Generator

Fill in your invoice details and print or save as PDF. No account, no watermark, no data sent.

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Office & Productivity

Age Calculator

Calculate your exact age in years, months, days, hours, and minutes from a birthdate.

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Office & Productivity

Time Zone Converter

Compare multiple time zones simultaneously and convert a meeting time across the world.

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Office & Productivity

Statistics Calculator

Enter a data set and get mean, median, mode, standard deviation, variance, and percentiles.

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Office & Productivity

Meeting Cost Calculator

Calculate the real cost of a meeting based on hourly rates and number of participants. Live timer included.

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Office & Productivity

Working Days Counter

Count business days between two dates, excluding weekends and public holidays for France, Belgium, Switzerland, and Canada.

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Office & Productivity

Countdown to Date

Set a target date and see a live countdown in days, hours, minutes, and seconds. Save multiple countdowns in your browser.

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Office & Productivity

Number Formatter

Format numbers for any locale: thousands separators, decimal symbols, and currency display. Compare formats side by side.

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Office & Productivity

Bill Splitter

Split a restaurant bill equally or by custom amounts. Add a tip percentage and see exactly what each person owes.

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Sport & Fitness

Running Pace Calculator

Convert between pace (min/km or min/mi), speed (km/h), and finish time for any distance.

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Sport & Fitness

VMA / VO₂max Estimator

Estimate your VMA and VO₂max from a Cooper 12-min test, a time trial, or a recent race result.

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Sport & Fitness

Race Time Estimator

Predict your 5K, 10K, half-marathon, and marathon finish times from any known race performance.

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Sport & Fitness

Training Pace Zones

Generate your complete running training pace table from VMA or threshold pace.

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Sport & Fitness

Elevation Effort Calculator

Adjust your running effort and time for elevation gain using Naismith's rule and equivalent flat distance.

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Sport & Fitness

Heart Rate Zone Calculator

Calculate your 5 heart rate training zones from your max HR or age. Includes Karvonen formula with resting HR.

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Sport & Fitness

Cycling FTP & w/kg Calculator

Calculate your Functional Threshold Power (FTP) from a 20-min or 60-min test and get your full Coggan training zones.

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Sport & Fitness

Calorie Burn Estimator

Estimate calories burned during any physical activity using MET values. Enter activity, duration, and body weight.

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Sport & Fitness

Swimming Pace Calculator

Convert between swimming pace per 100m/yd, total distance, and finish time. Calculates CSS pace.

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Sport & Fitness

Run Split Planner

Enter a target finish time and distance to get per-kilometer or per-mile split times.

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Sport & Fitness

VO₂max from Race Time

Estimate your VO₂max from a recent race performance using the Daniels/VDOT formula.

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Sport & Fitness

1RM Calculator

Estimate your one-rep max using the Epley, Brzycki, and Lombardi formulas from any rep count.

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Sport & Fitness

Steps → Distance & Calories

Convert daily step count to distance (km/mi) and calories burned based on your height, weight, and pace.

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Sport & Fitness

Training Load (CTL/ATL/TSB)

Enter daily TSS values and calculate your Chronic Training Load (fitness), Acute Training Load (fatigue), and Form (TSB).

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Sport & Fitness

Pace Band Generator

Enter your target finish time for a marathon, half marathon, or 10K and get a printable pace band with splits every 5 km.

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Sport & Fitness

Stretching Timer

Guided stretching routine with configurable hold time and rest time. Audio cue when each stretch is done.

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Sport & Fitness

Walk / Run Interval Timer

Configurable walk/run interval timer. Set run and walk durations, number of rounds, and get audio cues for each switch.

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Health & Wellness

Body Indices Calculator

Calculate BMI, Corpulence Index, WHR, WHtR, ideal weight, and body fat percentage from your measurements.

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Health & Wellness

TDEE Calculator

Calculate your Total Daily Energy Expenditure (TDEE) and Basal Metabolic Rate using three validated formulas.

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Health & Wellness

Menstrual Cycle Tracker

Predict your next period, ovulation window, and fertile days. Track your cycle history locally.

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Health & Wellness

Sleep Cycle Calculator

Find optimal wake-up or bedtime based on 90-minute REM sleep cycles.

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Health & Wellness

Water Intake Calculator

Calculate your daily water recommendation based on weight, activity level, and climate.

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Health & Wellness

Blood Pressure Interpreter

Enter your systolic and diastolic readings and get an instant WHO/ACC classification with risk level and recommendations.

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Health & Wellness

Alcohol Units Calculator

Calculate total alcohol units from your drinks, compare to weekly health guidelines, and see time until sober.

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Health & Wellness

Sleep Need Calculator

Find out how many hours of sleep you need based on age and activity level, and calculate your current sleep debt.

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Health & Wellness

Ovulation Window Calculator

Calculate your fertile window and estimated ovulation date from your last period and average cycle length.

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Finance & Money

Loan & Mortgage Calculator

Calculate monthly payments, total interest, and view a full amortization schedule for any loan.

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Finance & Money

Compound Interest Calculator

Calculate how an investment grows with compound interest, optional recurring contributions, and custom compounding periods.

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Finance & Money

VAT / Tax Calculator

Add or remove VAT from any price. Supports all tax rates with French VAT presets.

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Finance & Money

Savings Goal Calculator

Find out how long to reach a savings target, or how much to save per month to reach it on time.

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Finance & Money

Currency Converter

Convert between 30+ currencies using live exchange rates from a public API.

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Finance & Money

Budget Planner

Enter your income and expense categories to instantly see your monthly balance and savings rate.

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Finance & Money

Inflation Calculator

Calculate the equivalent purchasing power of a sum between any two years using historical CPI data for France and the US.

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Finance & Money

Fuel Cost Calculator

Calculate the fuel cost for any trip from distance, consumption (L/100 km or MPG), and fuel price.

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Finance & Money

Freelance Rate Calculator

Calculate your minimum daily or hourly freelance rate from your desired net income, expenses, and billable days per year.

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Finance & Money

Rent vs Buy Calculator

Compare the total cost of renting versus buying a home over time and find the break-even point in years.

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Web & Accessibility

Color Contrast Checker

Check foreground and background color contrast ratio against WCAG AA and AAA accessibility standards.

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Web & Accessibility

Open Graph Preview

Preview how your page looks when shared on Google, Twitter, Facebook, and LinkedIn.

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Web & Accessibility

IP / CIDR Calculator

Break down any CIDR block into network address, broadcast, host range, subnet mask, and host count.

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Web & Accessibility

URL Parser & Inspector

Dissect any URL into its components: scheme, host, port, path, query parameters, and fragment.

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Web & Accessibility

HTML Entity Encoder

Encode special characters to HTML entities (named, decimal, or hex) and decode them back.

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Web & Accessibility

Meta Tag Generator

Generate a complete set of HTML meta tags: title, description, Open Graph, Twitter Card, viewport, charset, and canonical.

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Web & Accessibility

HTTP Header Explainer

Paste HTTP response headers and get a plain-English explanation of each directive with security and caching insights.

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Web & Accessibility

Typography Scale Generator

Generate a modular type scale from a base size and ratio. Preview each step and copy the CSS custom properties.

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Web & Accessibility

Color Palette Generator

Pick a base color and generate complementary, analogous, triadic, and split-complementary palettes with HEX, RGB, and HSL values.

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Web & Accessibility

robots.txt Generator

Build a valid robots.txt file with a guided interface. Add rules per user-agent, set crawl delay, and include your sitemap.

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Webperf & SEO

SERP Preview

Preview how your page title and meta description appear in Google search results.

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Webperf & SEO

JSON-LD Schema Generator

Generate JSON-LD structured data for Article, FAQ, Product, Organization, and more.

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Webperf & SEO

CSS Minifier & Beautifier

Minify or beautify CSS code client-side. Reports byte savings.

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Webperf & SEO

JS Minifier

Strip comments and whitespace from JavaScript code. Runs entirely in your browser.

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Webperf & SEO

Sitemap XML Validator

Validate sitemap.xml structure: required tags, lastmod format, changefreq values, and URL count.

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Webperf & SEO

Sitemap Generator

Generate a valid sitemap.xml from a list of URLs with optional lastmod, changefreq, and priority.

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Webperf & SEO

Cache-Control Builder

Build Cache-Control HTTP headers by selecting directives. Copy-ready output with inline explanations.

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Webperf & SEO

Heading Structure Checker

Paste HTML and visualize the H1–H6 heading hierarchy. Flags missing H1, duplicate H1, and skipped levels.

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Webperf & SEO

Keyword Density Analyzer

Analyze keyword frequency in text. Stop-word filtering, density percentage, and CSV export.

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Webperf & SEO

Core Web Vitals Reference

Interactive reference for LCP, CLS, INP, FID, FCP, and TTFB — thresholds, diagnosis tips, and fix priorities at a glance.

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Webperf & SEO

Image ALT Text Auditor

Paste HTML and instantly list all images with missing, empty, or suspiciously short alt attributes.

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Webperf & SEO

Redirect Chain Checker

Enter a URL and trace its full redirect chain — every hop, status code, and final destination displayed step by step.

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Webperf & SEO

robots.txt Tester

Paste a robots.txt file and test whether a given URL is allowed or blocked for any user-agent.

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Kitchen & Cooking

Kitchen Multi-Timer

Run multiple simultaneous kitchen timers with custom labels. Web Audio beep on expiry.

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Kitchen & Cooking

Cooking Time Calculator

Find cooking times and internal temperatures for meats, fish, vegetables, eggs, and more.

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Kitchen & Cooking

Recipe Scaler

Scale any recipe up or down for a different number of servings. Handles grams, ml, cups, and spoons.

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Kitchen & Cooking

Nutritional Values

Look up calories, protein, carbs, fat, fiber, and sodium for 60+ common foods. Meal builder included.

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Kitchen & Cooking

Cooking Unit Converter

Convert cooking measurements: cups, fl oz, tbsp, tsp, ml, g, oz, lb, °F, °C.

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Kitchen & Cooking

Egg Timer

Precise egg cooking timer: soft (3 min), medium (6 min), hard (10 min), or custom. Animated SVG ring.

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Kitchen & Cooking

Baking Substitutions

Find baking ingredient substitutes with exact ratios. Filter by vegan, dairy-free, or gluten-free.

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Kitchen & Cooking

Yeast Converter

Convert between fresh yeast, active dry yeast, and instant yeast for any quantity.

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Kitchen & Cooking

Coffee Ratio Calculator

Calculate the perfect coffee-to-water ratio for espresso, pour-over, French press, Aeropress, and cold brew.

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Kitchen & Cooking

Bread Hydration Calculator

Enter flour weight and hydration percentage to get exact water, salt, and starter quantities in grams.

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Kitchen & Cooking

Food Shelf Life Guide

Look up how long any food lasts in the fridge, freezer, or pantry. Search by ingredient with storage tips.

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Kitchen & Cooking

Alcohol Dilution Calculator

Calculate how much water to add to reduce a spirit or wine to a target ABV. Works for any volume and starting strength.

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Kitchen & Cooking

Cocktail Ratio Builder

Scale classic cocktail ratios for 1, 6, or 12 servings. Adjust proportions and see exact measures in ml and oz.

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Knitting & Hobbies

Knitting Needle Size Converter

Convert knitting needle sizes between US, metric (mm), and UK systems instantly.

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Knitting & Hobbies

Yarn Yardage Estimator

Estimate how many meters or yards of yarn you need for a knitting or crochet project based on weight and stitch count.

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Knitting & Hobbies

Row & Stitch Counter

Count rows and stitches while knitting or crocheting. Multiple counters with localStorage persistence.

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Knitting & Hobbies

Knitting Gauge Calculator

Calculate finished dimensions from stitch gauge, or find how many stitches to cast on for a target size.

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Knitting & Hobbies

Embroidery Thread Converter

Convert embroidery thread numbers between DMC, Anchor, and Madeira brands with color swatches.

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Knitting & Hobbies

Crochet Hook Size Converter

Convert crochet hook sizes between metric (mm), US letters, and UK/Canadian sizes with a full reference table.

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Knitting & Hobbies

Seam Allowance Calculator

Enter your finished garment dimensions and seam allowance to get exact cutting dimensions. Supports cm and inches.

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Knitting & Hobbies

Paint Color Mixing Guide

Enter a target color and see how to mix it from primary acrylic or watercolor paints, with approximate ratios.

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Knitting & Hobbies

Fabric Yardage Estimator

Calculate how many metres or yards of fabric you need from garment dimensions and fabric width (laize).

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Gardening

Sowing Calendar

Find the best time to sow seeds indoors and outdoors for vegetables and flowers by month.

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Gardening

Fertilizer NPK Calculator

Calculate the actual nitrogen, phosphorus, and potassium content from a fertilizer NPK ratio and application weight.

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Gardening

Plant Spacing Calculator

Calculate how many plants fit in a bed and optimal spacing from bed dimensions and plant spacing requirements.

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Gardening

Watering Needs Estimator

Estimate how often and how much to water your plants based on species, pot size, season, and climate.

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Gardening

Moon Phase Garden Planner

View current and upcoming moon phases and get gardening recommendations for sowing, pruning, and harvesting.

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Gardening

Companion Planting Guide

Look up companion planting relationships: which plants help each other grow and which should be kept apart.

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Gardening

Compost C:N Ratio Calculator

Enter the weights of your brown and green materials to calculate the carbon-to-nitrogen ratio and get composting advice.

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Gardening

Soil pH Guide

Enter your soil pH and see which vegetables, fruits, and flowers grow best, plus which amendments to add.

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Reading & Books

Book Tracker

Track your current books, reading progress by page, and reading history — all in your browser via localStorage.

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Reading & Books

Reading Pace Estimator

Calculate your reading speed in pages per hour and estimate time remaining to finish a book.

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Reading & Books

Reading Goal Tracker

Track your annual reading goal — books read vs target — with progress projection and daily page targets.

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Reading & Books

Book Note Organizer

Save quotes and notes from books you are reading. All stored locally in your browser. Export as plain text.

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Reading & Books

Reading Stats Dashboard

Visualise your reading history from the Book Tracker: books per month, pages per day, and genres read.

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Brain Training

IQ Score Estimator

Convert a raw IQ score to a percentile and classification using standard deviation scales.

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Brain Training

Pattern Sequences Quiz

Identify the next number in a sequence. Arithmetic, geometric, Fibonacci, and alternating patterns.

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Brain Training

Mental Arithmetic Trainer

Practice mental arithmetic with timed addition, subtraction, multiplication, and division exercises.

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Brain Training

Memory Span Test

Test your digit span (working memory capacity) by remembering increasingly long sequences of numbers.

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Brain Training

Reaction Time Test

Measure your visual reaction time over multiple trials and compare to population averages.

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Brain Training

Stroop Effect Test

Name the ink colour of color words as fast as possible. Measures cognitive interference and response inhibition.

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Brain Training

Visual Memory Test

Memorize a grid of highlighted squares, then recreate it from memory. Grid grows harder with each correct round.

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Brain Training

Attention & Focus Test

Click the targets, ignore the distractors. Measures sustained attention, accuracy, and false-positive rate over 60 seconds.

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