Pea Gravel Calculator for Pea Stone Paths, Fire Pits and Play Areas
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Walk the path in late April and you can read the whole job off the ground. Where the stone has thinned to bare soil, where the frost has pushed the edging out of line over the winter, and where last year's layer has migrated downhill into the ferns. Measure those spots. This pea gravel calculator turns them into tons.
Pea stone goes down once the ground has stopped moving
Frost heaves gravel drives and walks here every spring, and a shallow rounded stone layer moves more than most. Lay a new path over ground that is still thawing and it settles unevenly as the soil lets go of the water underneath.
The sensible window opens at the end of mud season and runs to the fall freeze. It comes later in the hills and the North Country than along the Merrimack.
Two jobs that ride on that timing. A path or fire-pit surround wants a firm, drained subgrade, so wait for it. A play area wants its depth checked and topped up in spring, because that is when the winter's settling shows.
What to pace off before you open the tool
A path. Walk its length with a tape rather than stepping it out, and take the width at the average, not at the widest point where it opens out.
A fire-pit circle. Diameter straight across, through the middle, at the widest.
A fall zone. Follow the equipment manual for the footprint. It is bigger than the frame in every direction.
A patio or seating area. The finished rectangle, edging to edging.
Depth is where pea stone is different. More is not better, and the useful range is narrow.
| Where it is going | Depth |
|---|---|
| Paths, patios, seating | 2 to 3 inches |
| Fire-pit surround | 3 inches |
| Dog run | 2 to 3 inches |
| Play fall zone, maintained | 9 to 12 inches |
Under 2 inches and the ground shows through by August. Over 3 and walking on it feels like dry sand. The play depth is the exception, and it is set by the equipment, not by comfort.
The fields, and the box to untick
Shape first: rectangle, circle, or multiple areas totaling up to five pieces, which is handy for a path with two seating bays off it. Length, width and diameter in feet. Depth in inches, from 0.25 up to 24. Then the material select, since the weight rides on it.
Untick the 5% compaction and spillage box for loose cover. Nothing here gets compacted. Round the tonnage up instead, and keep the spare for the traffic line next spring.
Cubic yards, tons and cubic feet come back together, and Email my quote will send them to you.
Light underfoot, not light in the truck
Rounded 3/8 inch stone feels soft to walk on and weighs almost exactly what crushed stone does: about 2,800 lb per cubic yard, which is 1.40 tons. The rounded shape packs tighter than people expect, so there is less air in a yard than the look of it suggests.
Check the screen with this: cubic yards = area sq ft x depth in, divided by 12, divided by 27. Tons = yards x 1.40.
Coverage, if you want landmarks rather than arithmetic. One ton spreads about 116 square feet at 2 inches, 77 square feet at 3 inches, and only 19 square feet at the 12 inch play depth.
A 14 foot fire-pit circle on a camp lot
Hypothetical. Three inches of pea stone around a pit, held by steel edging.
- 7 x 7 x 3.14 = 153.9 sq ft
- 153.9 x 0.25 ft = 38.5 cu ft
- 38.5 / 27 = 1.43 cu yd
- 1.43 x 1.40 = 2.00 tons
Stone does not burn and rain drains straight through it overnight, which is the whole argument for it round a fire. Lay a compacted skim of stone dust underneath first if chair legs are going to sink.
A fall zone under a swing frame
Hypothetical. Seventeen feet square, maintained at 12 inches.
- 17 x 17 = 289 sq ft
- 289 x 1 ft = 289 cu ft
- 289 / 27 = 10.70 cu yd
- 10.70 x 1.40 = 14.98 tons
That is the number people get wrong by a factor of five, because they picture a path and price a pit. At a foot deep a ton covers about 19 square feet, a patch not much over four feet square. Check the equipment manual for the required depth before ordering, and plan on topping it back up each spring. What the tonnage buys is landscape pea stone, not certified playground surfacing: the required depth, the fall-zone footprint and the maintained depth all come from the equipment manufacturer's instructions rather than from us.
Edging, and the rake in April
Round stone rolls. Almost every complaint about pea stone spreading comes back to edging that is missing, or edging that has settled flush with the surface.
Set steel, aluminum, timber or paver edging an inch proud of the finished stone. Frost will shift it over a winter, so walk the line in spring and knock it back true before you top up.
On anything steeper than about one in twenty, rain and boots will move the stone downhill regardless. Use a honeycomb stabilizing grid under it, or switch that stretch to angular walkway gravel, which interlocks. A long path can change material where the grade changes; nobody will notice but you.
Rake the traffic line level twice a year and hold back a bucket or two for the bare patch that always appears at the gate.
Two other tools are worth knowing about before you order. Decorative beds and borders take larger stone and are sized as river rock by the ton. A seating area that has to hold table and chair legs steady wants a compacted layer underneath, which is base stone underneath rather than more pea stone on top.
Once the tonnage looks right, set a quantity and a date on the product page. How delivery is arranged explains what the truck needs, since loose round stone wants a firm, contained drop spot rather than a slope. The rest of the calculators cover loam, mulch, sand and base.
Common questions
Do I enter the depth loose, or after it has been walked in?
Loose, as spread. Pea stone is not compacted and it barely settles, which is why the 5% box comes off. The one place depth is measured after the fact is a play area, where the manual asks for a maintained depth and you top up to it.
There is a round landing at the bottom of the camp steps. How do I work that out?
Circle mode, diameter across the widest part. By hand: halve the diameter, square it, multiply by 3.14. An 8 foot landing is about 50 square feet, and at 3 inches that is 12.6 cubic feet, 0.47 yards, or roughly 0.65 tons.
Is there a quick check on the tonnage before I order?
Divide your square footage by the coverage. One ton at 2 inches covers about 116 square feet, and at 3 inches about 77. A 200 square foot patio at 3 inches should land near 2.6 tons, and if your arithmetic says 26 you have the depth in feet instead of inches.
Three inches of pea stone and three inches of river rock over the same bed give different tons. Why?
Weight per yard. Pea stone runs about 2,800 lb, river rock about 2,700. It is a small gap here, but against loam at 2,200 or mulch at 600 it is enormous, so set the material before reading the tonnage.
Should I add the 5% for a path that gets a lot of use?
No, but do round up. The allowance is built for material that gets rolled or driven on, and pea stone is neither. What a path actually needs is a reserve for the worn line, so take the next half ton rather than relying on a box.
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3/8 inch natural pea gravel, priced by the ton, delivered free.
