Compost C:N Ratio Calculator
Free compost C:N ratio calculator. Balance brown and green materials to achieve the ideal 25-30:1 carbon-to-nitrogen ratio for fast, efficient composting.
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Calculate Your Compost C:N Ratio
The carbon-to-nitrogen (C:N) ratio is the key to successful composting. Microorganisms need the right balance of carbon for energy and nitrogen for protein production. Our calculator helps you mix brown and green materials to achieve the ideal 25-30:1 ratio for fast decomposition without odors.
Understanding the C:N Ratio
The C:N ratio represents the proportion of carbon to nitrogen in organic materials. Browns (dry leaves, cardboard, straw) are carbon-rich with high ratios (60:1 to 400:1). Greens (grass, food scraps, manure) are nitrogen-rich with low ratios (10:1 to 30:1). Combining them correctly creates ideal conditions for decomposition.
C:N Ratio Formula
C:N = ÎŁ(Weight Ă Carbon%) / ÎŁ(Weight Ă Nitrogen%)Why Balance Your Compost?
Faster Decomposition
The ideal 25-30:1 ratio provides optimal conditions for microorganisms to break down materials quickly.
Eliminate Odors
Too much nitrogen (low ratio) causes ammonia smells. Proper balance produces earthy-smelling compost.
Better End Product
Balanced compost creates nutrient-rich humus perfect for gardens and plants.
How to Use This Calculator
Common Composting Scenarios
Kitchen Scraps + Leaves
Balance nitrogen-rich food waste with dry autumn leaves for backyard composting.
Grass Clippings + Cardboard
Mix fresh lawn clippings with shredded cardboard to prevent matting and odors.
Manure Composting
Add carbon sources to nitrogen-rich animal manures for proper decomposition.
Large-Scale Composting
Calculate ratios for municipal or farm composting operations handling diverse materials.
Frequently Asked Questions
The ideal range is 25:1 to 30:1. This provides enough carbon for energy and nitrogen for microbial protein synthesis. Ratios above 30:1 decompose slowly; below 25:1 may produce ammonia odors.