Cubic feet = area (sq ft) × depth (in ÷ 12). Cubic yards = cubic feet ÷ 27, with waste applied first. Estimated tons = cubic yards × tons per yard.
How gravel volume is figured
Gravel is sold by volume in cubic yards, not by square feet of ground. You need the area you are covering—length × width for a rectangle, or total square feet for odd shapes you have already measured—then multiply by depth in feet (inches ÷ 12).
There are 27 cubic feet in one cubic yard. A 20 ft × 4 ft path (80 sq ft) at 3 inches deep is 80 × 0.25 = 20 cu ft, which is about 0.74 cubic yards before waste. Suppliers often deliver in quarter-yard steps; rounding up avoids a second trip.
Compaction and raking leave dips, so a small waste percentage (5% is a fair default) keeps you from running short. Steeper use or soft subgrade may need 10%.
How deep should gravel be?
2 inches can work for a firm existing base or decorative topping. 3 inches is common for foot paths and side yards. 4 inches suits patios and light parking. 6 inches is closer to a base layer under pavers or a driveway—confirm with your supplier if you need separate base and surface stone.
Pea gravel feels softer underfoot; crushed stone locks tighter. Depth math is the same; only ordering names change.
Worked example: 20 × 4 ft path, 3″ deep
Area = 20 × 4 = 80 sq ft. Depth = 3″ = 0.25 ft. Volume = 80 × 0.25 = 20 cu ft. With 5% waste: 21 cu ft. Cubic yards = 21 ÷ 27 ≈ 0.78 → order 1 cubic yard (rounded up). At 1.4 tons/yd³, that is about 1.4 tons on the truck scale—verify with your quarry.
Quick FAQ
- Cubic yards or tons? Order bulk by cubic yards (volume). Tons help you compare quotes and truck limits; density varies by stone and moisture.
- Pea gravel vs crushed? Same volume formula. Pea gravel is often lighter per yard (~1.25 tons/yd³); crushed stone is often ~1.4.
- Mulch or topsoil instead? For bark or soil depth, use a mulch or topsoil calculator on a separate page—do not use gravel depth rules for organic mulch.
- Delivery minimums? Many suppliers have a 1–3 yard minimum; the calculator shows raw math so you can see if bagged stone at the store is cheaper for tiny jobs.
About this tool
howmuchgraveldoineed.com is a browser-only gravel quantity estimator for paths, patios, and small driveways. Nothing you type is uploaded. Published by R7Global.
Questions: r7global@gmail.com