Topsoil Volume Calculator
Calculate how many cubic yards of topsoil to order for raised beds, lawn repair, or planting projects. Accounts for soil depth, mix type, and compaction so you don't over-order or run short mid-project.
About this calculator
Topsoil volume calculations convert a flat bed's dimensions and required depth into the cubic yards used for bulk landscape material ordering. The formula is: cubic yards = (bedLength × bedWidth × (soilDepth / 12)) / 27 × soilMix × compactionFactor. Dividing soil depth (in inches) by 12 converts it to feet, and dividing the resulting cubic feet by 27 converts to cubic yards — the standard unit for bulk soil delivery. The soilMix multiplier adjusts volume when blending amendments; a 50/50 topsoil-compost blend may have a different density and settlement rate than pure topsoil. The compactionFactor accounts for the fact that loose delivered soil will settle 10–20 % once watered and planted, so ordering slightly more prevents low spots and exposed roots. Together these factors give you an accurate order quantity for your supplier.
How to use
You have a raised bed that is 12 ft long, 4 ft wide, and you need 6 inches of new topsoil. You're using pure topsoil (soilMix = 1) and a compaction factor of 1.15 to cover settlement. Calculate: (12 × 4 × (6/12)) / 27 × 1 × 1.15 = (12 × 4 × 0.5) / 27 × 1.15 = 24 / 27 × 1.15 = 0.889 × 1.15 ≈ 1.02 cubic yards. Order one cubic yard of topsoil — most suppliers sell in quarter-yard increments, so round up to 1.25 yards for a small buffer.
Frequently asked questions
How many cubic yards of topsoil do I need for a 4-inch deep garden bed?
For a 4-inch deep application you need 0.012 cubic yards per square foot of bed area, or roughly 1 cubic yard for every 81 sq ft. For example, a 10 × 10 ft bed (100 sq ft) at 4 inches deep requires approximately 1.23 cubic yards before adding a compaction buffer. Always add 10–15 % extra to account for settling after watering, especially with loose, fluffy topsoil blends. Most bulk suppliers deliver in 1-yard minimums, so plan your bed dimensions around efficient order quantities.
What is a compaction factor and why does it matter for topsoil orders?
When bulk topsoil is delivered it is loose and aerated, containing a high percentage of air voids. Over time — especially after rain and foot traffic — those voids compress and the soil volume shrinks by 10–20 %. The compaction factor (typically 1.10–1.20) pre-accounts for this shrinkage by increasing your order quantity so the finished, settled depth matches your target. Ignoring compaction is the most common reason gardeners run short of topsoil partway through a project. If you're filling a raised bed with a wooden frame, compaction is especially important because you can't easily add more soil after planting.
How do I convert cubic feet of topsoil to cubic yards when ordering from a supplier?
Divide the total cubic feet by 27, since one cubic yard equals 3 ft × 3 ft × 3 ft = 27 cubic feet. For example, a bed that calculates to 54 cubic feet requires 54 / 27 = 2 cubic yards of topsoil. Bulk landscape suppliers universally quote topsoil in cubic yards, while bagged topsoil is sold in cubic feet — typically 0.75 or 1 cubic foot per bag. For areas over 2 cubic yards, bulk delivery is almost always more economical than bagged product.