Garden material planning · Updated November 3, 2026
Soil and compost volume calculator
Estimate soil, topsoil or compost volume across multiple areas with project-specific depths, in cubic feet and cubic yards.
Enter one area and its planned depth per line as area × depth in square feet and inches. For example, 120 × 4. The calculator totals each area's volume; it does not recommend a depth or account for settling, grading or delivery conditions.
Enter positive area × depth pairs and calculate.
Use a separate line whenever an area has a different depth. Areas with the same depth can be combined. This is a geometric volume estimate; supplier quantities may differ because of uneven ground, settling, moisture, loading and delivery practices.
Sources and method
- University of Minnesota Extension: Promote healthy soil in your garden (reviewed November 3, 2026): discusses soil testing and adding organic matter; it does not prescribe a universal amount, so use a project-specific depth.
- Henrico County Extension: How to Calculate Amounts of Peat Moss, Compost and Topsoil to Purchase (reviewed November 3, 2026): gives bulk volume as total area multiplied by desired depth in feet and divided by 27 cubic feet per cubic yard.
- Cornell Cooperative Extension: Calculating Volume Needed of Topsoil, Compost or Mulch (reviewed November 3, 2026): provides a reference table using square feet and a user-selected depth.
Method: cubic feet = area in square feet × depth in inches ÷ 12. Cubic yards = cubic feet ÷ 27. The conversion matches the Henrico County Extension formula. The entered depth is your assumption, not a recommendation; volume delivered can vary with site and supplier conditions.
How it works
Enter one area × depth pair per line in square feet and inches. The estimator shows the calculation for each region, totals cubic feet and converts the sum to cubic yards.
Good to know
Quick answer: how much topsoil do I need?
For each region, multiply its area in square feet by its planned depth in inches and divide by 12 for cubic feet. Add the regional volumes, then divide by 27 for cubic yards. Depths are project-specific; this calculator does not recommend them. Reviewed November 3, 2026.
How do I convert square feet and inches to cubic yards?
For each area, multiply square feet by depth in inches and divide by 12 to get cubic feet. Add those volumes; divide the total by 27 because one cubic yard contains 27 cubic feet. Henrico County Extension presents the area × depth formula for bulk topsoil and compost.
What depth should I use?
Use the depth specified for your planting, grading or landscape plan and local conditions. The estimate does not choose a depth; intended use, existing soil, drainage and site conditions can change the plan.
Will the delivered amount match this estimate exactly?
Not necessarily. This is a geometric volume estimate. Uneven ground, settling, moisture, loading and supplier measurement practices can affect the delivered amount. Confirm ordering units and quantities with the supplier.
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