Pea Gravel Calculator
This pea gravel calculator works out how much a path, patio, playground or dog run needs, in cubic yards, tons and bags.
Path, Patio or Bed
Playground Surfacing
Fall protection needs far more depth than landscaping does, this is the number people get wrong.
Pea Gravel Cost
How to use the Pea Gravel Calculator
Depth is the decision that matters here. For landscaping, two inches suits a path or bed and three a patio, deeper is harder to walk on, not better, because pea gravel is rounded and shifts underfoot.
For a playground it is a different question entirely. Fall protection depth is set by the height a child can fall from, and it starts at nine inches. Use the playground tab, not the landscaping one.
Bagged pea gravel is normally half a cubic foot to the bag. Past about a cubic yard, around 54 bags, bulk delivery is cheaper even with the fee.
Pea Gravel Cost prices by the ton, the yard or the bag. Bags suit a small border and get expensive quickly beyond that; the tab shows you where the crossover falls instead of making you work it out.
Pea Gravel formula
volume = length × width × depthcubic yards = cubic feet ÷ 27tons = cubic yards × 2,800 ÷ 2,000bags = cubic feet ÷ bag size, rounded up
Pea gravel runs about 2,800 lb per cubic yard, or 1.4 tons.
| Use | Depth | Per 100 sq ft |
|---|---|---|
| Garden path or bed | 2 in | 0.62 yd³ |
| Patio or seating area | 3 in | 0.93 yd³ |
| Dog run | 3 to 4 in | 0.93 to 1.23 yd³ |
| Playground, 5 ft fall height | 9 in | 2.78 yd³ |
| Playground, 8 to 10 ft fall height | 12 in | 3.70 yd³ |
Worked example
A 20 ft × 4 ft path at 2 inches, 5% waste:
- Area: 80 sq ft. Volume: 80 × 0.1667 = 13.33 ft³
- Cubic yards: 0.49, plus 5% = 0.52 yd³, about 0.73 tons, or 28 bags
A 20 ft × 15 ft play area at the 9 inch depth for a 5 ft fall height:
- Area: 300 sq ft. Volume: 300 × 0.75 = 225 ft³
- Cubic yards: 8.33, plus 10% = 9.17 yd³, about 12.8 tons
Nearly four times the footprint, but eighteen times the material. Depth dominates.
What the result means
Pea gravel is rounded, and everything about it follows from that. It is comfortable to walk on and it drains beautifully. It also migrates: without a solid edge it will be in your lawn within a season, and it never locks up the way angular crushed stone does. That is why it is not a driveway material and not a paver base.
The playground depths are safety figures, not preferences. Nine inches of pea gravel is rated for falls up to five feet and twelve inches for up to eight, and those depths assume the material stays loose and uncompacted, which means raking it back into the fall zones under swings regularly, because that is exactly where it gets displaced.
The tonnage here is an estimate. Volume is exact; loose stone density moves with moisture and source.
Common mistakes
- Using landscaping depth under playground equipment. Two inches of pea gravel is a path. Nine inches is fall protection. They are not the same product decision.
- Laying it without edging. Rounded stone rolls. Steel, stone or timber edging is not optional for pea gravel.
- Going deeper than three inches for walking. It gets harder to walk on, not more durable. Depth does not fix migration; edging does.
- Using it as a paver base or driveway. Rounded stone will not compact or interlock. Use angular crushed stone for anything structural.
- Skipping the fabric. A geotextile layer underneath stops the gravel disappearing into soft ground and slows weeds.
- Letting playground gravel compact. The safety rating depends on it staying loose. Rake it level, especially under swings and slides.
Frequently asked questions
How much pea gravel do I need?
Multiply length by width by depth in feet and divide by 27 for cubic yards. A 20 by 4 foot path at 2 inches deep is 13.3 cubic feet, or about 0.52 cubic yards with a 5 percent allowance.
How deep should pea gravel be?
Two inches for a path or bed, three for a patio, three to four for a dog run. For playground fall protection it is nine inches for falls up to five feet and twelve inches up to eight, far deeper than any landscaping use.
How many bags of pea gravel in a cubic yard?
A cubic yard is 27 cubic feet, so 54 bags at the usual half cubic foot per bag. That is also roughly where bulk delivery becomes cheaper than bagged.
How much does a cubic yard of pea gravel weigh?
About 2,800 lb, or 1.4 tons. Wet material weighs more. Ask your supplier for their own figure if you are buying by weight.
Is pea gravel good for a driveway?
No. The stones are rounded, so they never lock together, they rut under tyres and spread out of the drive. Angular crushed stone is the driveway material. Pea gravel suits paths, beds and play areas.
Does pea gravel need edging?
Yes. Rounded stone rolls, and without a physical edge it migrates into lawns and beds within a season. Steel, stone or timber edging, plus geotextile fabric underneath, is the standard installation.
Sources and assumptions
Volume is exact geometry. Density is taken at 2,800 lb per cubic yard, a mid-range value from landscape supply charts, and tonnage is presented as an estimate because loose stone density moves with moisture and source.
Playground depths follow the US Consumer Product Safety Commission’s public playground safety handbook, which lists pea gravel among the acceptable loose-fill surfacing materials with depth requirements set by critical fall height. Those depths assume uncompacted material maintained at depth.
Confirm quantities with your supplier, and playground surfacing requirements with the equipment manufacturer, before ordering.