Pea gravel is small, smooth, rounded stone, usually about ⅜ inch across, that is popular for garden paths, patios, dog runs, play areas and the joints between stepping stones. Because it is sold both in small retail bags and in bulk by the yard or ton, the hardest part of a pea gravel project is usually translating your layout into an order. This pea gravel calculator does that: enter the length, width and depth of the area and it returns the cubic yards, the approximate weight in tons and the number of 0.5 cubic-foot bags, which is the most common bag size at home centers.
For larger stone such as driveway base or crushed rock, use the gravel calculator. If you are setting pavers or flagstone with pea gravel in the joints, start with the paver calculator for the base and bedding layers.
How to use the pea gravel calculator
- Choose a rectangle or circle and enter the dimensions of the area. Break L-shaped or curved paths into simple sections and add the results.
- Enter the finished depth. Two to three inches is typical for walkways and patios; play areas are usually much deeper (see the table below).
- Keep at least 10% in the extra field to allow for settling, uneven subgrade and stone that migrates into the soil.
- Leave the density at 1.4 tons per cubic yard unless your supplier lists a different figure for their product.
- Enter a bulk price per yard or ton, or a bag price, to compare buying in bags against a bulk delivery.
Formula
A cubic yard is 3 ft × 3 ft × 3 ft = 27 ft³, per the NIST unit definitions. Bags are always rounded up because you cannot buy part of one.
Worked example
A side-yard path is 24 ft long and 3 ft wide, with 3 inches of pea gravel over landscape fabric.
- Area: 24 × 3 = 72 ft².
- Volume: 72 × (3 ÷ 12) = 18 ft³, which is 18 ÷ 27 = 0.67 yd³.
- Add 10%: 0.67 × 1.10 = 0.73 yd³ (19.8 ft³).
- Weight at 1.4 tons per yard: 0.73 × 1.4 ≈ 1.03 tons, roughly 2,050 lb.
- Bags: 19.8 ÷ 0.5 = 39.6, so buy 40 bags.
Forty bags is a lot to haul in a car, and around the point where a single bulk delivery of one cubic yard often costs less. Enter both prices to check.
Pea gravel depth by use
| Use | Typical depth |
|---|---|
| Walkway or garden path | 2–3 in over landscape fabric |
| Patio or seating area | 3 in, ideally over a compacted crushed-stone base |
| Dog run | 3–4 in, with good drainage underneath |
| Joints between stepping stones | Depth of the stones (usually 1.5–2 in) |
| Playground surfacing | Much deeper; see CPSC guidance below |
For home playgrounds, the U.S. Consumer Product Safety Commission's Outdoor Home Playground Safety Handbook says to maintain a minimum of 9 inches of sand or pea gravel for equipment up to 5 feet high, and notes that an initial fill of 12 inches compresses to about 9 inches over time. For a play area, enter 12 inches as the depth and add edging to keep the stone contained. Taller equipment needs a different surfacing material, such as wood chips, engineered wood fiber or rubber mulch.
Bags or bulk?
Each 0.5 ft³ bag covers about 2 ft² at 3 inches deep or 3 ft² at 2 inches. Bags are convenient for small jobs and top-ups, but a cubic yard is 54 bags' worth of stone, so for anything beyond a small path a bulk delivery is usually cheaper and far less lifting. Ask whether your supplier has a minimum delivery and a per-trip fee.
Caveats and assumptions
- Pea gravel is loose and rolls underfoot. Edging (steel, aluminum, stone or timber) keeps it in place and stops it migrating into lawns.
- Density varies with moisture and grading; 1.4 tons per cubic yard is a typical mid-range value for dry stone, not a guarantee.
- Bag sizes differ between brands. Check the cubic-foot figure printed on the bag rather than its weight.
- This calculator does not size a sub-base. Patios that will carry furniture benefit from 2–4 inches of compacted crushed stone beneath the pea gravel.
Frequently asked questions
How many bags of pea gravel do I need?
Multiply length × width × depth in feet to get cubic feet, add about 10%, and divide by the bag size. For 0.5 ft³ bags that is two bags per cubic foot: a 24 × 3 ft path at 3 inches needs about 40 bags.
How much does a yard of pea gravel weigh?
Roughly 1.3 to 1.5 tons (2,600–3,000 lb) when dry. This calculator uses 1.4 tons by default; your supplier can confirm the figure for their stone.
How much area does a ton of pea gravel cover?
At 1.4 tons per yard, a ton is about 0.71 yd³ or 19.3 ft³. That covers about 116 ft² at 2 inches deep, or 77 ft² at 3 inches.
Do I need landscape fabric under pea gravel?
It is not required, but a woven landscape fabric slows weeds and stops the gravel sinking into soft soil. It does not stop weeds that germinate in debris on top of the gravel.
Is pea gravel good for a patio?
Yes, for a casual seating area. Use about 3 inches over a firm base and edging on all sides. Chair legs can sink into deep loose stone, so some people prefer a stabilized gravel or pavers for dining areas.
Sources
- U.S. CPSC — Outdoor Home Playground Safety Handbook — loose-fill surfacing materials and recommended depths
- U.S. Geological Survey — Construction Sand and Gravel Statistics — what construction gravel is and how it is produced
- NIST — Unit Conversion — cubic foot, cubic yard and ton definitions
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.