Small rounded stone, sized by project
Pea Gravel Calculator
Tell it what you are building — a path, a patio, a dog run, a play area — and it sets a working depth, then returns cubic yards, tons, and bags. It also shows what one ton covers at that depth and whether bags or a bulk load come out cheaper.
Volume is area × depth. Tons use the bulk density above — a supplier number beats a table every time. Confirm the grade and color before the truck is loaded.
0.76 yd³ · 1.08 tons · 42 bags
How much pea gravel you need, in one pass
Pea gravel is a finishing stone, not a structural one. It is the small rounded pebble — about 3/8 inch, the size of a garden pea — that goes on paths, patios, play areas, and garden beds. Because it is rounded, it never locks together the way crushed stone does, so every pea gravel order is really two decisions: how deep the layer needs to be for what you are building, and whether the tonnage works out cheaper in bags or in bulk.
The volume math is the same everywhere: area in square feet times depth in feet gives cubic feet, and 27 cubic feet make a cubic yard. What changes from project to project is the depth. A garden bed wants an inch or two. A path wants two to three. A patio wants three over a compacted base. A play area under a swing set is a safety surface, and the CPSC handbook lists nine inches of pea gravel for equipment up to five feet of fall height. Same stone, same formula, ten times the volume.
Tons are where estimates usually go wrong. Pea gravel runs roughly 100–110 lb/ft³ loose, which puts a cubic yard near 2,700–2,970 lb, or about 1.35–1.48 short tons. Suppliers who quote a lighter 96 lb/ft³ will tell you a ton covers 120 sq ft at two inches; at the 105 lb/ft³ this calculator starts with, it covers about 114. Both are correct for their material — the difference is density, not arithmetic. If the yard gives you a number, use it.
How deep pea gravel should be, project by project
Depth by project — and what breaks if you miss
Depth is the only input that changes the order by a factor of ten. The table is the same list the calculator’s project presets come from, with the failure mode attached, because “how deep” is really “what goes wrong at the wrong depth.”
| Project | Preset | Published range | Too thin | Too deep |
|---|---|---|---|---|
| Garden bed or border | 2 in | 1–2 in | Fabric shows, weeds push through at the edges. | Buries crowns and traps moisture against trunks. |
| Walkway or path | 2.5 in | 2–3 in | Bare patches and visible fabric after a season of footfall. | Feels loose, like walking on marbles. |
| Patio or seating area | 3 in | 2–3 in | Base shows through where chairs and tables sit. | Furniture legs sink and drag; the surface never firms up. |
| Fire pit surround | 3 in | 2–3 in | Looks unfinished next to the pit. | Stone sits above the pit rim and spills into the burn area. |
| Driveway top course | 3 in | 2–3 in over a base | Base aggregate is visible and reads as a construction site. | Ruts under tires. Rounded stone never locks together. |
| Dog run or kennel | 3.5 in | 3–4 in | Dogs dig through to soil; mud at the gate. | Waste disappears into deep stone and odor lingers. |
| Drainage trench | 8 in | 6–12 in | Not enough void around the pipe to carry water. | Extra cost with no extra drainage; fabric still required. |
| Play area | 9 in | 9–12 in | Below the handbook depth for the fall height involved. | Stone buries equipment footings and is hard to rake level. |
Two details matter as much as depth. First, an edge: rounded stone has nothing holding it in place, so paths and driveways want steel, timber, or stone edging set about a half inch above the finished surface. Second, fabric: a woven geotextile under beds and paths keeps soil from pumping up into the stone and keeps the stone from sinking. Neither changes your volume — but without them, you will be reordering in two years.
Pea gravel is also the wrong answer for some jobs. It ruts under tires, it is not an ADA-accessible surface, and it scatters out of high-traffic lanes. Where the surface has to carry cars or stay firm for a wheelchair, the answer is angular crushed stone or a stabilized surface — not a different depth of pea gravel.
Coverage per ton, per yard, and per bag
These are the numbers behind most “one ton covers 120 sq ft” charts. The first three columns move with density; the cubic-yard column does not, because a cubic yard is a cubic yard whatever the stone weighs. That is why a yard-based quote and a ton-based quote for the same pile can look like different projects.
Compare nine materials at 2, 3, and 4 inches in the gravel coverage per ton guide. Each estimate shows its assumed density.
| Depth | 1 ton covers | 1 yd³ covers | 1 bag covers | 100 sq ft needs |
|---|---|---|---|---|
| 1 in | 229 sq ft | 324 sq ft | 6.0 sq ft | 0.31 yd³0.44 tons |
| 2 in | 114 sq ft | 162 sq ft | 3.0 sq ft | 0.62 yd³0.88 tons |
| 2.5 in | 91 sq ft | 130 sq ft | 2.4 sq ft | 0.77 yd³1.09 tons |
| 3 in | 76 sq ft | 108 sq ft | 2.0 sq ft | 0.93 yd³1.31 tons |
| 4 in | 57 sq ft | 81 sq ft | 1.5 sq ft | 1.23 yd³1.75 tons |
| 6 in | 38 sq ft | 54 sq ft | 1.0 sq ft | 1.85 yd³2.63 tons |
| 9 in | 25 sq ft | 36 sq ft | 0.7 sq ft | 2.78 yd³3.94 tons |
Read the table backwards when you already have material. Two tons of 3/8 inch pea gravel spread over a 12 by 20 foot patio (240 sq ft) lands at about 1.9 inches — enough for a bed, thin for a patio. The same two tons over a 90 sq ft walkway is closer to 5.1 inches, which is exactly the path depth you wanted. Weight spread over area is depth; that is the whole trick.
Bags or bulk? The crossover is about half a cubic yard
Retail bags are convenient and expensive. A 0.5 cubic foot bag holds half a cubic foot, so 54 bags make a cubic yard — and at typical bag prices that is several times what the same yard costs in bulk. Below roughly half a cubic yard, bags usually win because bulk suppliers have delivery minimums or will not sell a partial load. Above it, bulk wins by a wide margin even after a delivery fee.
For other bag sizes, see how many bags of gravel make a cubic yard. Check the label for volume in ft³; a weight in lb needs a density estimate.
The table prices each common project both ways at $5 per bag and $50 per ton. Your numbers will differ — the calculator takes your local prices and redoes this comparison on the volume you actually need.
| Project | Depth | Volume | Bags | Bag cost | Bulk cost |
|---|---|---|---|---|---|
| 10 × 10 ft patio | 3 in | 0.93 yd³1.31 tons | 50 | $250 | $66cheaper here |
| 12 × 12 ft patio | 3 in | 1.33 yd³1.89 tons | 72 | $360 | $95cheaper here |
| 3 × 30 ft walkway | 2.5 in | 0.69 yd³0.98 tons | 38 | $190 | $49cheaper here |
| 10 × 10 ft dog run | 3.5 in | 1.08 yd³1.53 tons | 59 | $295 | $77cheaper here |
| 20 × 20 ft play area | 9 in | 11.11 yd³15.75 tons | 600 | $3,000 | $788cheaper here |
| 10 × 10 ft garden bed | 2 in | 0.62 yd³0.87 tons | 34 | $170 | $44cheaper here |
What it weighs, and whether it fits in your truck
At 105 lb/ft³ a cubic yard of pea gravel weighs about 2,835 lb, or roughly 1.42 short tons. That number surprises people who have hauled a yard of mulch, which weighs a fraction of it. A half-ton pickup is not a one-ton truck in the way the name suggests — modern payload ratings land around 1,300–1,700 lb, which is under half a yard of pea gravel once you count the driver and fuel.
The table converts each payload into the volume of pea gravel it can legally carry. If your project needs more than one trip, price a delivered load against the extra trips before you decide.
| Vehicle | Typical payload | Pea gravel it can carry | Bags equivalent |
|---|---|---|---|
| Half-ton pickup | 1,500 lb | 0.53 yd³ | 28 bags |
| 3/4-ton pickup | 2,500 lb | 0.88 yd³ | 47 bags |
| 1-ton pickup | 3,500 lb | 1.23 yd³ | 66 bags |
| Utility trailer | 4,000 lb | 1.41 yd³ | 76 bags |
Pickup-truck math is the most common reason a pea gravel project turns into three trips. If your total is over about half a cubic yard, ask for a delivered price. If you are hauling anyway, load the stone over the axle rather than at the tailgate, tarp it, and weigh at a scale if you are close to the limit.
Ordering checklist
Name the grade, not just “pea gravel”
Sizes run from 1/4 inch to 1/2 inch, and “pea gravel” in one yard is “#8 stone” in another. 3/8 inch washed is the safe default for paths and play areas.
Ask for the density on the ticket
Tons per cubic yard or lb/ft³. Two yards can quote the same pile at 1.35 and 1.45 tons per yard. Use their number and the tonnage here will match the invoice.
Confirm washed vs unwashed
Unwashed stone carries fines that pack down and muddy the look on a patio. Washed costs a little more and stays loose.
Decide on the edge first
Steel, timber, or stone edging set a half inch above the finished grade. Buy it before the stone arrives, not after the first rain.
Round up, then rake
Order the extra 10% — settling, spillage, and fabric wrinkles always eat some. A cubic yard left over is a border you can finish later; half a yard short is a second delivery fee.
Check access before you buy bulk
A dump truck needs about 10–12 feet of clear width and a place to spread. Narrow gates and terraces sometimes make bags the cheaper answer despite the unit price.
Worked examples
Three orders that cover most of what people search for. All three use 105 lb/ft³ and include a 10% cushion, which is what the calculator adds by default.
A walkway or path
3 ft × 30 ft at 2.5 in
- Volume
- 0.76 yd³
- Weight
- 1.08 tons
- Bags equivalent
- 42
Roughly 0.7 cubic yards. One delivery, or about 38 bags if you would rather not take a truck.
A patio or seating area
12 ft × 12 ft at 3 in
- Volume
- 1.47 yd³
- Weight
- 2.08 tons
- Bags equivalent
- 80
Over a compacted base, with edging. Bags stop making sense here — bulk is cheaper by a wide margin.
A play area
20 ft × 20 ft at 9 in
- Volume
- 12.22 yd³
- Weight
- 17.33 tons
- Bags equivalent
- 660
A safety surface, not a decorative cover. Confirm the required depth against the current CPSC handbook for your equipment height.