Compost Calculator
Turn garden bed dimensions into litres of compost and whole bags to buy.
Your result
Litres needed
113.27 L
Cubic metres
0.11 m³
Cubic yards
0.15 yd³
Bags needed
3 bags
Compost volume and bag quantities
Multiply bed length × width × depth in metres. One cubic metre equals 1,000 litres. Add your optional percentage allowance, divide by the labelled bag volume and round up. A 2 × 1.5 m bed with 5 cm compost needs 150 L, or four 40 L bags, before extra allowance.
Use the bag’s volume, not its weight. The depth and allowance are your choices, not universal planting recommendations. This calculates compost for covering or filling beds, not the carbon-to-nitrogen ratio of a compost heap.
Frequently asked questions
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