How to calculate pea gravel
- Split the project into rectangles — a driveway with a parking pad or an apron is two or three sections, not one guess. Add each as its own area.
- Enter the depth — presets start at 1–4 inches; type anything custom.
- Set the waste allowance — 10% default; reduce it for a well-formed path on firm ground.
- Weight, if you need it — the calculator shows the sourced-from-range figures only; check the "use my supplier's density" box once you have their lb/ft³ value.
- Get the cost — price per bag for bagged, price per yard or per ton plus delivery for bulk (the per-ton box only applies once a density is set).
The formulas
Volume (cu ft) = Area (sq ft) x depth (in) / 12
Volume (cu yd) = Volume / 27
Weight (lb) = Volume (cu ft) x density (lb/cu ft)
US short tons = Weight (lb) / 2,000
Bags = round-up(Adjusted cu ft / bag size)The density behind the weight range: The Engineering ToolBox — Dirt and Mud Densities — Gravel, dry: 105 lb/ft³ (1,680 kg/m³); Gravel, wet: 125 lb/ft³ (2,000 kg/m³). Review date 2026-11-07. Real deliveries vary with moisture, grading and washing; the range reflects that.
Worked example
A single-section 10 × 10 ft path at 2 inches: 100 sq ft × 2 ÷ 12 = 16.7 cu ft ≈ 0.62 cu yd. With 10% allowance: 18.3 cu ft. At the sourced dry density (105 lb/ft³) that's about 1,925 lb ≈ 0.96 short tons. Zero bags — 37 of the 0.5 cu ft retail bags would be 18+ trips. Bulk wins at these sizes; the comparison panel quantifies it once prices are in.
Measuring tips
- Driveways taper — measure the narrowest and widest edges and use the average length and width, or split into two rectangles.
- Measure depth, don't guess: set a board edge across the path and measure down from it.
- Curved walkways: use the centerline curve measured with a tape, splitting odd shapes into sections.
Common pea gravel mistakes
- Ordering loose bulk tonnage and expecting bagged math to match — loose gravel spreads, then compacts.
- Confusing pea gravel (rounded, 3/8") with crushed stone with angular edges, which packs and behaves differently.
- Forgetting containment (edging): pea gravel migrates; a membrane and edging keep the calculated depth in place.
- Ordering to exactly one ton with no allowance; deliveries usually land on round numbers — ask for the closest sensible size.
Frequently asked questions
How many cubic yards of pea gravel do I need?
Multiply your area in square feet by the depth in inches and divide by 12 for cubic feet, then by 27 for cubic yards. A 10 × 10 ft path at 3 inches is 25 cubic feet, about 0.93 cubic yards.
How many tons is a cubic yard of pea gravel?
It depends on the specific gravel and moisture. Using our sourced dry-to-wet range (105–125 lb/ft³) a cubic yard runs about 1.7–2.1 US short tons. Ask your supplier for their figure — or enter it in the calculator for an exact conversion.
How deep should pea gravel be for a driveway?
Depth presets are options, not engineering: light foot-traffic paths often use 1–2 inches over prepared ground; vehicle-surface jobs typically use deeper material and a separate base layer. Confirm with your supplier or a contractor for vehicle loads.
How much does a 0.5 cu ft bag of pea gravel cover?
At 2 inches deep, one 0.5 cu ft bag covers about 3 square feet; at 1 inch, about 6 square feet. Driveways are almost always cheaper delivered in bulk.
Why is gravel weight only a range?
Real weight varies with moisture, grading and supplier processing. We publish a range from a sourced density table and never present a single fabricated number — enter your supplier density for precision.