Why order extra? The headline number is the exact material your project needs. When you actually order, add about 5–10% on top — the “with 5% waste” figure in the result is a safe starting point. That margin covers what you lose to compaction, cuts around edges and corners, and ordinary spillage during handling. It is cheaper to have a little left over than to stop mid-job and wait on a second delivery.
Field notes
The 5–10% waste on topsoil isn't about spillage — it's settling. Freshly delivered screened soil fluffs up on the truck and loses roughly a tenth of its volume once it's spread and rained on. Rake to your finished grade, then add the loss back. If you're topping a lawn, cap the layer at ½ inch per pass so you don't smother the existing grass.
How the topsoil calculator works
The math behind the tool:
cubic yards = (length ft × width ft × depth ft) ÷ 27Material density
| Material | Density | Per cubic yard |
|---|---|---|
| Screened topsoil | 80 lb/ft³ | 1.08 tons |
Sources: Oregon State University Extension (soil and compost volume guidance).