browns & greens calculator

Add what you've got in parts — a part is any scoop you like, a bucket or an armful. The gauge shows your mix's carbon-to-nitrogen ratio; compost cooks best between 25:1 and 30:1.

This calculator needs JavaScript. The rule of thumb it automates: aim for roughly 2–3 parts browns (dry leaves, cardboard) per 1 part greens (food scraps, grass).

your mix

or search any item

your ratio

Add a material to get started.

how it works

C:N ratios don't average like percentages — a mix's ratio is total carbon over total nitrogen, which weights wet, dense greens far more than fluffy browns. This tool uses published extension values (Cornell, NRAES-54) with a dry-bulk correction per material, the same numbers shown on our item pages. Parts are volume, so precision past half a part is false comfort: compost is forgiving, and anywhere near the green zone works.