Compost Calculator
Compost rate = N need ÷ (N% × 50% availability).
- Compost tonnes per hectare and tons/acre with P-K credits and C:N recipe checks for piles.
Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.
How the Compost Calculator Works
Successful composting requires balancing carbon-rich 'brown' materials with nitrogen-rich 'green' materials. The ideal ratio is approximately 30:1 (carbon to nitrogen). This calculator helps you determine the right mix of materials.
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Step 1
Enter your desired total compost volume
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Step 2: Specify your target C
N ratio (30:1 is recommended)
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Step 3
The calculator determines the proportion of greens and browns needed
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Step 4
Review the volumes of each material type required
Use Cases
Creating optimal compost for garden amendments
Managing farm waste into valuable fertilizer
Reducing landfill waste through proper composting
Producing consistent, high-quality compost for sale
Tips
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Browns include dry leaves, straw, cardboard, and wood chips
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Greens include grass clippings, food scraps, coffee grounds, and manure
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Turn compost every 1-2 weeks to speed decomposition
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Proper moisture is key - compost should feel like a wrung-out sponge
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Hot composting (130-160F) kills weed seeds and pathogens
Common Mistakes
Adding too many greens, causing smelly, anaerobic conditions
Not maintaining adequate moisture levels
Making the pile too small to generate sufficient heat
Including meat, dairy, or diseased plants that attract pests
FAQs
What is the ideal C:N ratio for composting?
How long does composting take?
Why does my compost smell bad?
Can I compost in winter?
Related tools
Pick another tool to continue your calculation.
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Organic Fertilizer Calculator
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Compost Mix Calculator
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Compost Area Calculator
Calculate compost needed to cover a planting area.
Compost Application Rate – N Release
Calculate organic compost needed.
Compost Ratio Calculator
Calculate carbon to nitrogen ratio.