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.

Green materials (nitrogen-rich)

Brown materials (carbon-rich)

About Compost Ratio Calculator

The ideal Carbon-to-Nitrogen ratio for active composting is 25:1 to 30:1. Too much nitrogen (greens): smells like ammonia, too wet. Too much carbon (browns): too dry, decomposes slowly. Browns include dry leaves, cardboard, straw, sawdust. Greens include grass clippings, kitchen scraps, coffee grounds. Turn the pile every 1–2 weeks for faster decomposition. Optimal temperature: 55–65°C.