How to calculate how much gravel you need
Gravel is sold by volume (cubic yards) or by weight (tons), so every estimate starts with volume. Measure the length and width of the area, decide how deep the layer should be, and multiply the three numbers together.
Cubic feet = length (ft) × width (ft) × depth (ft)
Cubic yards = cubic feet ÷ 27
Tons = cubic yards × density (tons per cubic yard)
Depth is usually quoted in inches, so divide by 12 first: 3 inches is 0.25 ft. For a circle, the area is π × radius × radius; for a triangle it is base × height ÷ 2. If your space has an irregular outline, split it into rectangles, circles and triangles, calculate each one, and add the results together.
Finally, add a margin. Gravel settles and compacts once it is spread and raked, and a little is always lost at the edges, so ordering 5% to 10% extra is common. The calculator above does this for you with the extra percentage field. If you only need the raw volume of any material, use the cubic yard calculator.
Worked example: a gravel driveway
Say a driveway is 40 ft long and 12 ft wide, and you want a 4 inch layer of gravel.
- Area: 40 × 12 = 480 sq ft
- Depth: 4 ÷ 12 = 0.333 ft
- Volume: 480 × 0.333 = 160 cubic feet
- Cubic yards: 160 ÷ 27 = 5.926 cubic yards
- Weight at 1.4 tons per cubic yard: 5.926 × 1.4 = 8.30 tons
Adding 10% for compaction brings the order to 6.519 cubic yards, or about 9.13 tons. That is the number to give your supplier. Ordering a little over is far cheaper than paying a second delivery fee for a small top-up.
Gravel weight: how many tons in a cubic yard?
This calculator assumes 1.4 US short tons per cubic yard (about 2,800 lb). That is a typical planning figure: suppliers commonly quote somewhere between 2,500 and 3,000 lb per cubic yard for crushed stone and gravel, but the real number depends on the stone size, how wet it is and how tightly it is packed. Treat it as an assumption, not a measurement, and replace it in the density field with the figure your supplier gives you. Tons here are US short tons (2,000 lb); a metric tonne is about 2,205 lb, and results are shown in both.
| Material | Tons per cubic yard | Pounds per cubic yard |
|---|---|---|
| Crushed stone (¾ in) | 1.35–1.5 | 2,700–3,000 |
| Pea gravel | 1.35–1.45 | 2,700–2,900 |
| River rock | 1.3–1.5 | 2,600–3,000 |
| Road base (crushed aggregate) | 1.4–1.6 | 2,800–3,200 |
| Dry sand | 1.2–1.4 | 2,400–2,800 |
How deep should a gravel layer be?
The right depth depends on the job. As a rough guide, garden paths and decorative beds use 2 to 3 inches, a base under pavers or a patio is commonly around 4 inches, and driveways are often built up to 4 to 6 inches in total, sometimes in layers of different stone sizes. Always check the instructions for your product or project. The table shows how far gravel stretches at each depth.
| Depth | Sq ft covered by 1 cubic yard | Sq ft covered by 1 ton (at 1.4 t/yd³) |
|---|---|---|
| 2 in | 162 | 116 |
| 3 in | 108 | 77 |
| 4 in | 81 | 58 |
| 6 in | 54 | 39 |
Preparing a garden bed instead? Try the topsoil calculator or the mulch calculator.
Frequently asked questions
How much gravel do I need for a 10 × 10 ft area at 3 inches deep?
That is 25 cubic feet, or 0.926 cubic yards, which weighs about 1.30 short tons at 1.4 tons per cubic yard. In bags, that is 25 one-cubic-foot bags or 13 two-cubic-foot bags, before any extra for settling.
How many tons are in a cubic yard of gravel?
Usually about 1.4 short tons (roughly 2,800 lb), with a typical range of 1.3 to 1.5 depending on the stone and its moisture. Ask your supplier for their exact figure and enter it in the density field.
How much extra gravel should I order?
Most people add 5% to 10%. Gravel compacts when it is raked and driven on, and some is lost at the edges. Use the higher end for driveways and base layers that will be compacted with a plate compactor.
Is gravel sold by the ton or by the cubic yard?
Both are common. Bulk gravel is often priced per ton or per cubic yard, while bagged gravel is sold by cubic feet or by weight. Convert between them with the density figure: tons = cubic yards × 1.4 by default.
How many bags of gravel are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 54 half-cubic-foot bags, 27 one-cubic-foot bags, or 13.5 two-cubic-foot bags (round up to 14). For large areas, bulk delivery is usually cheaper than bags.
More free calculators
These calculators give estimates for planning only. Densities, bag sizes and coverage vary by supplier, so confirm quantities before you order.