Estimate how much compost your bin will produce based on size and fill ratio
Home composting is one of the most rewarding ways to recycle kitchen and garden waste into nutrient-rich soil conditioner. A well-managed compost bin can reduce your household waste by up to 30% while producing free compost for your garden beds, containers, and lawn. The key to successful composting is getting the right balance of green (nitrogen-rich) and brown (carbon-rich) materials. Greens include vegetable peelings, grass clippings, and coffee grounds. Browns include cardboard, dried leaves, straw, and woody prunings. The ratio of these materials affects both the speed of decomposition and the quality of the finished compost. Our compost bin calculator estimates the volume of finished compost your bin will produce based on its dimensions, fill level, and green-to-brown ratio. Compost typically shrinks to around 40% of the original input volume as organic matter breaks down, so a full 1,000-litre bin will yield roughly 400 litres of usable compost.
To estimate your compost yield: 1. Enter the bin length in metres. For a standard dalek-style bin, measure the diameter and use it for both length and width. 2. Enter the bin width in metres. 3. Enter the bin height in metres. Most standard compost bins are between 0.8 and 1.2 metres tall. 4. Set the fill level as a percentage. A 75% fill is typical since most bins are not completely full at any given time. 5. Choose your green-to-brown ratio. A 50:50 balance produces good compost but takes longer. A 70:30 ratio (more greens) decomposes faster but needs more attention to avoid odour. 6. Review the results showing bin volume, expected compost yield, weight estimate, and approximate time to maturity.
The compost bin calculator uses straightforward volume and ratio calculations: Bin Volume (litres) = Length x Width x Height x 1000 Filled Volume = Bin Volume x (Fill Level / 100) Compost Yield = Filled Volume x 0.4 Finished compost is approximately 40% of the original input volume. This accounts for the loss of water vapour, carbon dioxide, and the general compaction that occurs during decomposition. Weight Estimate = Compost Yield x 0.5 kg per litre Finished compost has an approximate density of 500 kg per cubic metre, or 0.5 kg per litre. Time to Mature varies by green-to-brown ratio: - 50:50 ratio: approximately 8 months - 60:40 ratio: approximately 6 months - 70:30 ratio: approximately 4 months Higher nitrogen content (more greens) accelerates microbial activity and speeds decomposition, provided the bin is turned regularly and moisture levels are maintained.
Inputs: Bin length: 1 m. Bin width: 1 m. Bin height: 1 m. Fill level: 75%. Green-to-brown ratio: 50:50.
Inputs: Bin length: 1.5 m. Bin width: 1.5 m. Bin height: 1.2 m. Fill level: 100%. Green-to-brown ratio: 70:30.
Inputs: Bin length: 0.7 m. Bin width: 0.7 m. Bin height: 0.9 m. Fill level: 60%. Green-to-brown ratio: 60:40.