Ordering · 7 min read
How Much Dirt Do I Actually Need? A Yard-by-Yard Guide
Ordering dirt by feel is how driveways end up with half a pile left over. Here is the simple math we walk customers through on the phone every day.
August 24, 2026 · Gulf Gravel & Dirt
Quick takeaways
- Length x width x depth in inches, divided by 324, equals cubic yards.
- Round up — a short load costs more than a slightly long one.
- Compacted materials lose about 20 percent of loose volume.
01
Start with length, width and depth
A cubic yard is a block of material three feet on every side — 27 cubic feet. Everything you order is priced and hauled in those blocks, so the whole job is converting your area into that unit.
Measure the length and width of the area in feet. Then decide the depth in inches. Multiply length by width by depth, then divide by 324. That gives you cubic yards. A 20 by 30 foot area at 3 inches deep works out to 20 x 30 x 3 = 1,800, divided by 324, or about 5.6 yards.
Round up, never down. Material settles, spreads unevenly, and nobody has ever finished a job wishing they had ordered less. A short pile means a second delivery fee for a fraction of a load.
02
Typical depths for common jobs
Top-dressing an existing lawn: 1/4 to 1/2 inch. Enough to fill in low spots without smothering the grass.
New sod or seed: 3 to 4 inches of topsoil or sandy loam so roots have somewhere to go before they hit clay.
Raised garden beds: fill the box. Measure the interior dimensions and treat the box height as your depth.
Gravel driveway: 4 to 6 inches of compacted base. Plan on the material losing roughly 20 percent of its loose volume once it is rolled.
Pool or trench backfill: measure the void, then add 10 to 15 percent for compaction in lifts.
03
Odd shapes and sloped yards
Break irregular areas into rectangles and circles, figure each one separately, and add the results. For a circle, multiply the radius by itself, then by 3.14.
Sloped or badly rutted ground eats more material than the flat math suggests. If you are filling low ground to level it, average the shallow end depth and the deep end depth and use that as your number.
If you would rather not do any of this, give us the area and what you are trying to accomplish and we will run it with you before you order.
Run your numbers
ESTIMATED
7.4 yd³
Order round numbers — material settles as it spreads.
Keep reading
Materials
Topsoil vs Fill Dirt: Which One Does Your Job Need?
They both look like dirt in the driveway, but using one where the other belongs is the single most expensive mistake we see homeowners make.
Drainage
Fixing Standing Water in a Houston Clay Yard
Gulf Coast clay holds water like a bathtub. Here is how we regrade a yard with dirt instead of digging a French drain across the whole thing.
Driveways
Building a Gravel Driveway That Does Not Wash Out
Base depth, gradation and crown are the three things that decide whether your driveway lasts a decade or ruts out by the second wet season.