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The Homestead Calculator

Free tools for the working homestead
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Compost Ratio Calculator

Find the ideal carbon-to-nitrogen ratio for your compost pile. Hot, fast composting happens at a C:N ratio of 25–30:1 — this calculator helps you get there.

Enter the pounds (or buckets) of each material you're adding. Adjust until your C:N ratio hits the sweet spot of 25–30:1.
Your C:N Ratio
—
:1
Status
—
 
Total Volume
—
lbs
of material
Pile Ready In
—
weeks (if turned)

C:N Ratios Reference
🟤 Browns (High Carbon)
Dry leaves — 60:1
Straw / hay — 80:1
Cardboard — 350:1
Sawdust — 400:1
Wood chips — 400:1
Newspaper — 175:1
Corn stalks — 60:1
🟢 Greens (High Nitrogen)
Grass clippings — 20:1
Kitchen scraps — 15:1
Chicken manure — 10:1
Cow manure — 20:1
Coffee grounds — 20:1
Fresh garden waste — 25:1
Alfalfa — 13:1

Frequently Asked Questions

What is the ideal carbon to nitrogen ratio for compost?

The ideal C:N ratio for fast, hot composting is 25–30:1. Below 20:1, the pile smells like ammonia and gets slimy (too much nitrogen). Above 35:1, decomposition stalls and the pile stays cool and dry (too much carbon).

What are browns and greens in composting?

Browns are high-carbon materials: dry leaves, straw, cardboard, sawdust, newspaper, and wood chips. Greens are high-nitrogen materials: fresh grass clippings, kitchen scraps, manure, coffee grounds, and fresh garden waste. A good compost pile needs roughly 3 parts browns to 1 part greens by volume.

How long does it take to make compost?

A well-managed hot compost pile with the right C:N ratio, adequate moisture, and regular turning can produce finished compost in 6–12 weeks. Cold composting (no turning, no monitoring) takes 6–12 months. Vermicomposting (worm bins) produces finished compost in 2–4 months.