How to Calculate Stone Coverage: A Complete Guide
Coverage is just volume spread over an area at a chosen depth. Once you know the simple 324 rule, you can work out how far any amount of stone will go — or how much you need for a given space.
"Stone coverage" answers a simple question: how much ground will a given amount of stone cover at the depth you want? Suppliers sell stone by volume (cubic yards) or weight (tons), but you plan a project by area (square feet). This guide gives you the formula, the coverage charts, and worked examples so the two always line up.
The Coverage Formula (the 324 Rule)
One cubic yard is 27 cubic feet, and there are 12 inches in a foot, so 27 × 12 = 324. That gives a clean shortcut for how much area a cubic yard covers at a given depth:
Coverage (sq ft per yd³) = 324 ÷ Depth in inches
Example: 324 ÷ 3 in = 108 sq ft per cubic yard
To flip it and find how much stone you need for a known area, multiply the area by the depth in feet and divide by 27. Our stone coverage calculator does both directions instantly.
Coverage Per Cubic Yard by Depth
| Depth | Coverage per cubic yard | Typical use |
|---|---|---|
| 2 inches | 162 sq ft | Decorative ground cover |
| 3 inches | 108 sq ft | Pathways, walkways |
| 4 inches | 81 sq ft | Patios, driveway top |
| 6 inches | 54 sq ft | Driveway base |
Coverage Per Ton by Material
If your stone is priced by the ton, coverage depends on density. Heavier material weighs more per cubic yard, so a ton of it covers less area. These figures are at 2 inches deep.
| Material | Density (tons/yd³) | Coverage per ton (2") |
|---|---|---|
| Pea gravel | 1.35 | ≈ 120 sq ft |
| Gravel | 1.40 | ≈ 115 sq ft |
| Crushed stone | 1.50 | ≈ 108 sq ft |
| River rock | 1.45 | ≈ 90 sq ft |
| Sand | 1.60 | ≈ 100 sq ft |
Worked Example
Covering a 240 sq ft Path at 3 Inches
Cubic yards: 240 sq ft × 0.25 ft ÷ 27 = 2.22 cubic yards
Cross-check with the 324 rule: 324 ÷ 3 = 108 sq ft per yard, and 240 ÷ 108 = 2.22 cubic yards ✓
In tons (crushed stone): 2.22 × 1.5 = 3.3 tons — add 10% for waste.
Things That Affect Coverage
- Depth is the biggest factor — doubling depth halves the area a given amount covers.
- Stone size: larger stone leaves bigger gaps, so it covers a little less than fine stone for the same weight.
- Compaction: compacted stone covers less area than loose stone but lasts longer.
- Waste: add 5–10% for uneven ground and spillage so you don't come up short.
For material-specific coverage, use the crushed stone calculator or gravel coverage calculator, and see how many yards of stone you need for the volume side of the math.
Calculate Coverage Instantly
Enter your area and depth (or a set volume) and get coverage worked out both ways — no manual math.
Open the Stone Coverage Calculator →