How to use the pea gravel calculator
- Pick the shape of the area: rectangle, circle (fire pit surrounds, tree rings), triangle, or enter a known total area.
- Enter the dimensions in feet (or meters in metric mode).
- Enter the depth. Pea gravel stones are about 3/8 inch, so you need enough depth for the stones to lock around each other without being so deep that they roll underfoot.
- Keep the default density unless your supplier gives a different number. Dry pea gravel is about 105 lb per cubic foot, or about 1.42 tons per cubic yard.
- Choose a bag size if you are buying from a garden center, and enter a price to estimate the cost.
Recommended pea gravel depths
- Walkways and garden paths: 2–3 inches over a compacted base or landscape fabric.
- Patios and seating areas: about 3 inches. Deeper pea gravel feels loose to walk on.
- Playgrounds: 9 inches or more. The U.S. Consumer Product Safety Commission's Public Playground Safety Handbook includes fine gravel in its loose-fill surfacing table at a 9-inch depth, and notes that loose fill compresses by roughly 25% over time, so about 12 inches should be installed to keep 9 inches in place. Confirm the fall height of your equipment against that table.
- Drainage around foundations or downspouts: 4–6 inches, often with fabric underneath.
The pea gravel formula
Volume (cu ft) = length (ft) × width (ft) × depth (in) ÷ 12
Cubic yards = cubic feet ÷ 27
Tons = cubic feet × density (lb/ft³) ÷ 2,000
The default density of 105 lb/ft³ (1,680 kg/m³) matches the figure for dry gravel in The Engineering ToolBox density tables. Wet gravel is heavier, about 125 lb/ft³, which matters if your supplier sells by weight from an outdoor pile after rain.
Worked example
A garden path is 20 ft long and 4 ft wide, filled 3 inches deep, with 10% extra for uneven ground.
- Area: 20 × 4 = 80 sq ft
- Volume: 80 × 3 ÷ 12 = 20 cu ft, plus 10% = 22 cu ft
- Cubic yards: 22 ÷ 27 = 0.81 yd³
- Weight: 22 × 105 = 2,310 lb = 1.16 tons
- Bags: 22 ÷ 0.5 = 44 bags of 0.5 cu ft
At this size, bulk delivery and bags are often close in price. Above about one cubic yard, bulk is almost always cheaper, though many yards have a minimum order or a delivery fee.
Tips for a pea gravel project
- Edge it. Pea gravel is round and migrates into lawns and beds. Steel, aluminum or paver edging set slightly above the gravel surface keeps it in place.
- Stabilize the base. For patios, put 2–4 inches of compacted crushed stone under the pea gravel, or use a plastic gravel-stabilizer grid. Our paver base calculator works for this layer.
- Fabric helps, but is not magic. Landscape fabric slows weeds from below, but seeds that land on top will still sprout.
- Rinse before spreading if the stone is dusty, especially around ponds.
Frequently asked questions
How much does a cubic yard of pea gravel weigh?
Dry pea gravel weighs roughly 2,800 lb per cubic yard, about 1.4 tons. Wet gravel can approach 3,400 lb (1.7 tons) per cubic yard.
How many bags of pea gravel are in a cubic yard?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cu ft. Always check the bag label, as some products are sold by weight instead of volume.
How much area does a ton of pea gravel cover?
At 105 lb/ft³, one ton is about 19 cubic feet. That covers about 76 sq ft at 3 inches deep, or about 114 sq ft at 2 inches deep.
Is pea gravel good for a patio?
Yes, it is inexpensive and drains well, but it shifts underfoot. A compacted crushed-stone base, firm edging and a depth of about 3 inches make it much more stable.
Should I use pea gravel or crushed gravel for a path?
Crushed gravel has angular edges that lock together and feels firmer. Pea gravel is rounder, softer on bare feet and looks more decorative but moves more.