♻️ Compost C:N Calculator
Enter your green and brown materials by weight to calculate the carbon-to-nitrogen ratio of your compost pile.
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MaterialWeight (lbs)C:N
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Carbon : Nitrogen ratio
Ideal finished compost: 10–15:1 | Active pile: 25–35:1
Ideal finished compost: 10–15:1 | Active pile: 25–35:1
Want a printable reference card?
Get the free Compost C:N quick-reference card — common materials with C:N ratios.
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Get the free Compost C:N quick-reference card — common materials with C:N ratios.
Preview the Free Reference Card →
Common C:N Ratios Reference
| Material | C:N Ratio | Type |
|---|---|---|
| Grass clippings (fresh) | 12–20:1 | Green |
| Food scraps / vegetable waste | 15–20:1 | Green |
| Coffee grounds | 20:1 | Green |
| Manure (cow) | 20:1 | Green |
| Manure (chicken) | 7:1 | Green |
| Legume residues | 15–30:1 | Green |
| Autumn leaves | 40–80:1 | Brown |
| Straw / hay | 40–100:1 | Brown |
| Cardboard | 350–500:1 | Brown |
| Sawdust (untreated) | 200–500:1 | Brown |
| Wood chips | 200–700:1 | Brown |
| Newspaper | 170:1 | Brown |