Topsoil Calculator for Raised Beds and Lawns
Updated 2026-07-30 · Yardly
Figure topsoil the same way for both jobs: square feet × depth in inches ÷ 324 = cubic yards. What changes is the depth — a new lawn needs 4–6 inches of soil, while a raised bed is filled to its full height, usually 10–12 inches. A 1,000 sq ft lawn at 4 inches takes about 12 cubic yards; a single 4×8 ft bed 10 inches deep takes about 1 yard.
One formula, two very different depths
The ÷ 324 comes from unit math: a cubic yard is 27 cubic feet, and spreading it 1 inch deep covers 324 square feet. So:
Square feet × depth (inches) ÷ 324 = cubic yards
The soil calculator handles the conversion, but the real estimating decision is the depth number you feed it — and that’s where lawns and raised beds part ways.
- Lawns are an area problem: a thin layer over a big footprint. Depth is set by what grass roots need.
- Raised beds are a container problem: a small footprint filled to the brim. Depth is set by the box — and by what you plan to grow.
Topsoil for a new lawn
University extension guidance is consistent on the floor: 4 inches of workable soil is the minimum for turf, and 6 inches or more is recommended for the deep roots that get a lawn through dry spells — the NMSU turfgrass establishment guide is explicit about both numbers. Builder-graded lots often have an inch or two of soil pushed over compacted subgrade, which is why new-construction lawns struggle.
Two practical adjustments before you order:
- Check what’s already there. Push a screwdriver into the ground at several spots; where it stops is roughly where topsoil ends. If you have 3 inches of decent soil, you’re buying a 1–3 inch top-up, not the full depth.
- Add 10–15% for settling. Fluffed, freshly delivered topsoil compacts as it’s graded and watered. Three loose inches settles toward two and a half.
Quick reference at common depths, per 1,000 sq ft:
| Depth | Cubic yards |
|---|---|
| 2 in (top-up over tilled soil) | ~6.2 |
| 4 in (extension minimum) | ~12.3 |
| 6 in (recommended) | ~18.5 |
If you’re building up low spots more than a few inches deep, don’t do it all with topsoil — bring the grade up with cheaper fill first and cap it with topsoil. The fill dirt calculator covers that split, and the new lawn project estimator bundles soil, seed or sod, and starter amendments into one materials list.
Topsoil for raised beds
A raised bed is just volume: length × width × height. A 4×8 ft bed filled 10 inches deep holds 4 × 8 × 0.83 ≈ 26.7 cubic feet — right at 1 cubic yard. Fill to about 2 inches below the rim, and expect the first-season level to drop as the mix settles; topping up next spring is normal, not a mistake.
Depth depends on the crops. Extension recommendations range from 6 inches as a working minimum (fine for lettuce, herbs, and other shallow rooters — see the Mississippi State Extension raised bed guide) up to 12 inches as the practical minimum for mixed vegetables, with tomatoes and other deep rooters happiest at 12–24 inches unless they can push into loosened ground below the frame.
The bigger difference from lawns: don’t fill the box with straight topsoil. Inside a frame there’s no earthworm-and-frost churn to keep pores open, so pure topsoil slumps into a dense, slow-draining block. Blend it — around 2 parts topsoil to 1 part compost is a common extension recipe, or equal parts topsoil, compost, and coarse sand on heavy clay. The raised bed soil calculator takes bed dimensions and splits the total into blend components.
Worked example: two beds and a patchy lawn
| Item | Size | Depth | Volume |
|---|---|---|---|
| Lawn top-up (tilled) | 800 sq ft | 2 in | 4.9 yd³ |
| Raised bed #1 | 4 × 8 ft | 10 in | 1.0 yd³ |
| Raised bed #2 | 4 × 4 ft | 10 in | 0.5 yd³ |
Total ≈ 6.4 yd³ → order 7 yards bulk. For the beds, take roughly a third of their 1.5 yards as compost instead of topsoil for the blend.
Bags make sense only at small volumes: topsoil bags are commonly 0.75–1 cubic foot, so a single cubic yard is 27–36 bags. One bed’s worth is a car-trunk errand; a lawn’s worth is a delivery.
Keep reading
- Deciding how to plant the lawn once the soil’s down? Sod vs seed for a new lawn compares cost and timing.
- Beds filled and planted — mulch for garden beds covers the surface layer that goes on top.
- The landscape material calculators guide maps every Yardly tool to the right material.
Frequently asked questions
How much topsoil do I need for 1,000 square feet of lawn?
At the commonly recommended 4-inch depth, 1,000 sq ft needs about 12.3 cubic yards (1,000 × 4 ÷ 324). At 2 inches — a typical top-up over tilled existing soil — it's about 6.2 yards. The [soil calculator](/calculators/soil) runs the conversion for any area and depth.
How deep should topsoil be for a new lawn?
University extension guidance puts the absolute minimum at 4 inches, with 6 inches or more recommended for deep rooting — see the [NMSU turfgrass establishment guide](https://pubs.nmsu.edu/_h/H509/index.html). Shallower soil means shallower roots, more watering, and a lawn that browns first in a dry spell.
Can I fill a raised bed with topsoil alone?
Not straight topsoil — inside a box it settles and compacts because there's no soil life reworking it from below. Extension programs recommend blending topsoil with compost (a common recipe is roughly 2 parts topsoil to 1 part compost, or equal parts topsoil, compost, and coarse sand) — see the [Mississippi State Extension raised bed guide](https://oac.msstate.edu/node/34738). The [raised bed soil calculator](/calculators/raised-bed-soil) splits the total into blend components for you.
How much does a cubic yard of topsoil weigh?
Roughly 2,000–2,700 pounds depending on moisture and organic content — call it a ton or more per yard. That's why anything beyond 2–3 yards is a delivery job, not a pickup-truck run: a half-ton truck is over its payload with a single heaped yard of damp topsoil.