Compost Calculator for Garden Beds
Estimate compost needed for a specified top-dressing depth or container fill, with litre and bag conversions.
How to use this tool
Length, width, compost layer depth; compost bag size. Check the units and use measurements from the growing space or instructions for your actual crop or product.
What the result means
Estimated total compost litres, cubic metres and bags. The result follows the inputs you provide; it does not replace inspection of your plants or the relevant product label.
Worked example
A 2.4 × 1.2 m raised bed filled to 30 cm needs 0.864 m³, or 864 litres: 22 bags of 40 litres, rounded up. A 5 cm compost layer over the same area needs 144 litres. Use the depth you intend to add, not the entire bed height.
Assumptions and limitations
Application depth must match gardening purpose; compost is not always sole fill material. This tool uses explicit arithmetic and your inputs; it does not connect to weather, location, product or soil databases.
litres = length_m × width_m × depth_cm × 10.
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