How much topsoil do I need?
Area times depth, converted to cubic yards — then one correction mulch doesn't need: soil settles. A loose yard off the truck becomes roughly 0.85 yards once it's raked, rained on and walked over, so fill and grading jobs need about 15% more than the geometry says. The calculator shows both numbers — the settled volume you'll end up with and the loose volume to order — and converts to tons, because many yards sell soil by weight.
A 1,000 sq ft new lawn bed at 4 in is 12.3 cu yd settled; with 15% settling, order 14.5 cu yd — about 14.5–19.6 tons, which is two or three dump-trailer loads, not a pickup.
How much does a yard of topsoil weigh?
Screened topsoil runs 2,000–2,700 lb per cubic yard — a ton to a ton and a third — depending on how much clay and how much water it's holding. Compost is about half that. If your supplier quotes by the ton, this is the conversion; if they quote by the yard, it's how you know whether your truck can carry it (a half-ton pickup can't carry a yard of topsoil, whatever the bed size).
| Cubic yards | Topsoil, tons | Compost, tons |
|---|---|---|
| 1 | 1.0–1.4 | 0.5–0.8 |
| 2 | 2.0–2.7 | 1.0–1.6 |
| 3 | 3.0–4.1 | 1.5–2.4 |
| 5 | 5.0–6.8 | 2.5–4.0 |
| 10 | 10.0–13.5 | 5.0–8.0 |
Topsoil at 2,000–2,700 lb/yd, compost at 1,000–1,600 lb/yd. Wet soil is at the top of each range.
Topsoil for common jobs
| Job | Area | Settled | Order (loose) | Tons |
|---|---|---|---|---|
| Top-dress a lawn, ½ in | 1,000 sq ft | 1.5 yd | 1.5 yd | 1.5–2.1 |
| Level low spots, 1 in average | 500 sq ft | 1.5 yd | 1.8 yd | 1.8–2.5 |
| New lawn bed, 4 in | 1,000 sq ft | 12.3 yd | 14.5 yd | 14.5–19.6 |
| New lawn bed, 6 in | 1,000 sq ft | 18.5 yd | 21.8 yd | 21.8–29.4 |
| Raise a garden bed, 8 in | 100 sq ft | 2.5 yd | 2.9 yd | 2.9–3.9 |
Settling 15% for fill and grading, none for top-dressing. Raised beds usually want a blended mix rather than straight topsoil — see the raised bed calculator.
How many bags of topsoil in a cubic yard?
The common 40 lb bag holds about ¾ of a cubic foot, so a cubic yard is 36 bags; the 1 cu ft bag takes 27. At $3 a bag that's $108 per cubic yard against $30–50 loose — and the bagged product is often the worse soil, screened fine enough to pour and short on structure. Bags make sense for a wheelbarrow's worth. For anything you'd measure in yards, get it delivered: with example prices the crossover is 1.1 yards, i.e. almost immediately.
Spreading soil or compost over an existing lawn only works if the grass can grow up through it — ¼ to ½ inch, never more than half the blade height. A ½ in top-dress over 1,000 sq ft is 1.54 cu yd, about 0.8–1.2 tons of compost. Piling it on to "fix" a low spot smothers the turf you were trying to help; do deep fills in lifts a season apart, or strip and re-seed.
What "topsoil" actually is
There's no standard. "Topsoil" from a bulk yard can be anything from screened, composted loam to whatever came off the last building site, and bagged "topsoil" is often mostly sand and ground bark. Ask for screened (lumps and roots removed) and whether it's been tested or amended; look at a handful — it should be dark, crumbly and smell like soil, not sour. For a seedbed, 4–6 inches of decent topsoil over the existing grade is the usual target; for garden beds, blend it with compost rather than using it straight.
Sources: Penn State Extension, Lawn Establishment (seedbed depth); University of Maryland Extension, Topdressing lawns; supplier published densities for screened topsoil and compost; USDA NRCS soil bulk-density ranges.