Compost Pile Ratio: 40 cu ft at 3:1 Browns to Greens
Calculate the volume of nitrogen-rich greens needed for a 40 cubic foot compost pile at the standard 3:1 ratio.
How to use this tool
- Enter the total target volume of your compost pile in cubic feet (3×3×3 ft = 27 ft³ is ideal).
- Enter the browns-to-greens ratio (3 is standard — 3 parts browns per 1 part greens).
- The calculator shows how many cubic feet of each material you need.
A 40 cubic foot pile is a substantial composting project — this calculator splits the volume correctly between browns and greens.
Frequently asked questions
- What is the best browns to greens ratio for compost?
- The ideal carbon-to-nitrogen (C:N) ratio for active composting is 25–30:1. By volume, this translates to roughly 3 parts browns (leaves, straw, cardboard) to 1 part greens (grass clippings, food scraps, fresh plant material).
- What are examples of browns and greens?
- Browns (high carbon): dry leaves, straw, wood chips, cardboard, paper. Greens (high nitrogen): fresh grass clippings, vegetable scraps, coffee grounds, fresh plant trimmings.