Compost Calculator
Brown-to-green ratio for a compost pile.
Add browns
60 lb
3 parts brown to 1 part green by volume
Greens (nitrogen, wet)
- Grass clippings
- Vegetable scraps
- Coffee grounds
- Fresh manure (herbivore)
- Spent flowers
Browns (carbon, dry)
- Dry leaves
- Cardboard, paper
- Straw, hay
- Wood chips, sawdust
- Pine needles
Pile basics
- Target pile: 3 ft × 3 ft × 3 ft minimum to retain heat
- Moisture: feel like a wrung-out sponge
- Turn weekly to add oxygen
- Hot pile: 130 to 150°F kills weed seeds and pathogens
- Finished: 3 to 6 months for hot, 9 to 12 for cold piles
The carbon-to-nitrogen target for compost is roughly 30:1. Greens average C:N of 20:1, browns around 50:1, so 3 parts browns to 1 part greens by volume gets you close. Smelly pile means too many greens. Slow pile means too many browns.
About
Add up your green nitrogen sources (grass, food scraps, coffee grounds). The tool gives you the matching browns (leaves, cardboard, straw) for a 30:1 carbon-to-nitrogen target.
How to use
- Enter pounds of greens.
- Read the suggested browns.
FAQ
Why 3 to 1 by volume?+
Greens average around 20:1 C:N, browns around 50:1. Mixed 3 parts brown to 1 part green by volume lands close to the 30:1 sweet spot for hot composting.