How to calculate pea gravel
Pea gravel is small, rounded stone — usually about ⅜ in across — that is smooth underfoot and drains freely. Because it is round, it doesn't lock together like crushed stone, so the right depth and a firm edge matter more than with other gravel.
- Measure the area in feet.
- Pick the project to set a typical depth, or enter your own.
- Convert to cubic yards (area × depth in inches ÷ 324) and then to tons at about 1.4 tons per yard.
- Add about 10% for settling and spreading.
Pea gravel formula
Tons = Cubic yards × 1.4
Bags (0.5 cu ft) = Cubic feet ÷ 0.5
Worked example: a 12 × 12 ft patio
A 144 sq ft patio 3 in deep needs 144 × 3 ÷ 324 = 1.33 cubic yards. With 10% extra that is 1.47 yards, or about 2.05 tons. In bags, the same volume is 39.6 cu ft — about 80 bags of 0.5 cu ft, which is why bulk delivery is usually cheaper for anything bigger than a small path.
How deep should pea gravel be?
| Project | Typical depth | Notes |
|---|---|---|
| Garden path | 2 in | Over a firm, compacted base and landscape fabric |
| Patio or seating area | 3 in | Deeper gravel shifts underfoot; keep it to 3 in |
| Dog run | 3–4 in | Easy to rinse; lay over a drainage base |
| Play area surfacing | 9 in or more | Check fall-height guidance; loose fill needs topping up |
| French drain / drainage trench | Fill the trench | Often washed ¾ in stone is preferred for drainage |
Pea gravel coverage chart
At 1.4 tons per cubic yard:
| Depth | Sq ft per ton | Tons per 100 sq ft | Bags (0.5 cu ft) per 100 sq ft |
|---|---|---|---|
| 2 in | 116 | 0.86 | 34 |
| 3 in | 77 | 1.30 | 50 |
| 4 in | 58 | 1.73 | 67 |
| 9 in | 26 | 3.89 | 150 |
Base and edging
- Dig out turf and soft soil, then compact 2–4 in of crushed stone base for patios and paths. The angular base gives the round pea gravel something firm to sit on — estimate it with the gravel calculator.
- Lay landscape fabric between base and pea gravel to slow weeds.
- Install strong edging (steel, aluminum, pavers or timber) higher than the gravel surface. Without it, pea gravel migrates into lawns and beds.
- For a firmer patio, stabilizing grid panels filled with pea gravel reduce shifting and make the surface easier to walk and roll furniture on.
Pros and cons of pea gravel
| Pros | Cons |
|---|---|
| Inexpensive and quick to install | Shifts underfoot and scatters without edging |
| Drains well; no standing water | Hard to push wheelbarrows, strollers and wheelchairs through |
| Smooth, comfortable surface | Not good on slopes — it rolls downhill |
| Wide range of colors | Needs occasional raking and topping up |
For driveways or sloped paths, use angular crushed stone instead, and for decorative beds with larger rock see the stone calculator.
Frequently asked questions
How much pea gravel do I need?
Multiply length × width in feet by depth in inches, divide by 324 for cubic yards, and multiply by 1.4 for tons. A 12 × 12 ft patio at 3 in needs about 1.9 tons before extra.
How many square feet does a ton of pea gravel cover?
About 116 sq ft at 2 in deep, 77 sq ft at 3 in and 58 sq ft at 4 in.
How many bags of pea gravel are in a yard?
A cubic yard is 27 cu ft, so it takes 54 bags of 0.5 cu ft.
How deep should pea gravel be for a patio?
About 3 in over a compacted base. Deeper pea gravel is harder to walk on because the stones roll.
How much does a yard of pea gravel weigh?
About 1.4 tons (2,800 lb) per cubic yard dry, a little more when wet.
Sources & standards
This calculator's formulas and default values are based on the following codes, standards and published data. Codes are adopted and amended locally, so check with your building department for permitted work. See how we build and check our calculators.
- Aggregate suppliers’ published bulk density for pea gravel (about 1.4 tons per cubic yard dry).
- U.S. Consumer Product Safety Commission, Public Playground Safety Handbook: loose-fill surfacing depths and maintenance.
- Unit conversions: cubic yards = sq ft × depth (in) ÷ 324; 1 yd³ = 27 ft³.