Compost Mix Ratio Calculator
Balance your compost's carbon-to-nitrogen ratio for fast, odor-free decomposition. Select your materials and quantities below.
Greens (Nitrogen-Rich)
Browns (Carbon-Rich)
How It Works
Compost needs the right balance of carbon (browns) and nitrogen (greens) to decompose efficiently. The ideal C:N ratio is between 25:1 and 30:1. This is because soil microbes use about 30 parts carbon for every 1 part nitrogen as they break down organic matter.
Why 30:1 Is Ideal
Microorganisms need carbon for energy and nitrogen to build proteins. At a 30:1 ratio, they have exactly what they need. Too much carbon (high C:N) and decomposition slows to a crawl. Too much nitrogen (low C:N) and you get ammonia odors and nitrogen runoff.
Tips
If too much carbon (high C:N): Add more greens like grass clippings, coffee grounds, or blood meal.
If too much nitrogen (low C:N): Add more browns like dry leaves, straw, or shredded paper.