MaterialCalculator
Free Compost Calculator

Feed your garden the right amount.

Calculate exactly how much organic compost you need to amend your soil for maximum plant growth.

Calculate Your Project

Project Diagram

L: 10 ftW: 5 ft3 in

Total Volume

Cubic Yards

Enter dimensions above

Estimated Weight

Tons

Based on Compost density (0.6 t/yd³)

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Number of 2 cu ft bags

bags

Recommended Depths for Compost

Project / Use CaseRecommended Depth
Topdressing Lawns0.25–0.5 inches
Soil Amendment (Tilled)1–2 inches
Raised Bed Mix (50% blend)6 inches

How to Calculate Compost Volume

Most landscaping suppliers sell compost by the cubic yard. To convert your project area to cubic yards, use this formula:

Volume (cu yd) = (Length × Width × Depth) ÷ 27

Our calculator also multiplies your cubic yard result by 0.6 tons/yd³ (the standard density for compost) to show estimated weight — essential if you are hauling the material yourself or need delivery pricing.

Pro Tips & Insights

1

For raised beds, a standard recipe is 50% topsoil, 30% compost, and 20% aeration material like perlite or sand.

2

When topdressing a lawn, aerate the soil first so the compost can reach the root zone.

3

Compost is very light compared to soil. A full cubic yard typically weighs between 1,000 and 1,200 lbs.

Frequently Asked Questions

How much compost do I need to amend my soil?
For general soil amendment, applying a 1 to 2-inch layer of compost and tilling it into the top 6 inches of soil provides excellent nutrient density. Use our calculator to find the cubic yardage for a 2-inch depth.
How many bags of compost are in a cubic yard?
A standard bag of compost from a garden center contains 1 cubic foot or 2 cubic feet of material. It takes 27 cubic feet to make a yard, meaning you need 13.5 (2 cu ft) bags to equal one cubic yard.
Can I plant directly in 100% compost?
No, planting in pure compost can burn plant roots due to high nutrient concentrations and poor drainage. Compost should always be mixed with topsoil or potting soil (usually no more than 30-50% compost).

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