Biology & Life Science
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Compost Ratio Calculator.
Compare measured brown and green material masses with a target brown-to-green ratio you provide.
Set your values
Results update as you type.
Results update automatically as you type.
Current ratio = brown mass ÷ green mass; additions are calculated to reach your entered target ratio. All rates, densities, and ratios are explicit inputs; no crop, species, product, or regional recommendation is inferred.
Use Cases
Check if your compost pile is balanced
Before adding materials, measure the brown and green masses and compare them to your target ratio to ensure optimal decomposition.
Example: You have 10 kg of leaves (brown) and 5 kg of grass clippings (green). Target 3:1. The calculator shows your ratio is 2:1, indicating too much green.
Adjust your mix to hit a specific ratio
If you know your target ratio, use the calculator to see how much more brown or green material you need to add to achieve it.
Example: With 8 kg brown and 2 kg green, target 3:1, the calculator shows you need 4 kg more brown to balance.
Frequently Asked Questions
- How does the Compost Ratio Calculator work?
- You enter the mass of brown material and green material in the same units, plus a target brown:green ratio (e.g., 3:1). The calculator compares your actual ratio to the target and shows whether your mix has too much brown, too much green, or is balanced.
- What is a good brown:green ratio for composting?
- A common target is 3:1 brown to green by volume, but many composters use 2:1 to 4:1. This calculator lets you set your own target ratio, so you can compare your materials against whatever ratio you aim for.
- Can I use any units for the masses?
- Yes, as long as you use the same unit for both brown and green materials. The calculator does not convert units, so if you enter pounds for brown, use pounds for green too.
Tips & Common Mistakes
Tips
- Use the same unit for both brown and green masses to get an accurate comparison.
- Aim for a target ratio that suits your compost ingredients; common targets are 2:1 to 4:1 brown:green.
- Measure materials as you add them to your pile to keep track of your running ratio.
- Remember that this calculator compares masses, not volumes; if you usually measure by volume, convert to mass for consistency.
Common Mistakes to Avoid
- Using different units for brown and green masses, which leads to an incorrect ratio.
- Forgetting to enter a target ratio, or entering it in the wrong format (e.g., entering 3 instead of 3:1).
- Assuming the calculator tells you the exact amount to add; it only compares your current mix to the target.
Last updated: August 13, 2026