A 12×20 ft driveway at 4 inches deep needs about 3.26 cubic yards of gravel — roughly 4.6 tons, including 10% extra. That assumes 1.4 tons per cubic yard, a typical figure for crushed stone. Plug in your own size with the free QtyLab gravel calculator and it does the math as you type.
Below: the formula, how much extra to order, a coverage chart by depth, and a short shopping list.
How many tons is a yard of gravel?
About 1.4 tons (2,800 lb) per cubic yard for typical crushed stone or gravel; most gravel falls between 1.3 and 1.5 tons. Going the other way, 1 ton is about 0.71 cubic yards.
| Cubic yards | Tons | Tons | Cubic yards |
|---|---|---|---|
| 1 | 1.4 | 1 | 0.71 |
| 2 | 2.8 | 5 | 3.6 |
| 3 | 4.2 | 10 | 7.1 |
| 5 | 7.0 | 15 | 10.7 |
| 10 | 14.0 | 20 | 14.3 |
The gravel formula
Gravel is bought by volume (cubic yards) or by weight (tons). Work out volume first, then convert.
- Cubic feet = length (ft) × width (ft) × depth (in) ÷ 12
- Cubic yards = cubic feet ÷ 27
- With waste = cubic yards × 1.10 (for 10% extra)
- Tons = cubic yards × density (tons per cubic yard)
Worked example, 12×20 driveway at 4 in: 12 × 20 × 4 ÷ 12 = 80 ft³. 80 ÷ 27 = 2.96 yd³. With 10% waste, 3.26 yd³. At 1.4 tons/yd³, that is 4.56 tons.
Density: why tons vary by stone
Tons depend on the stone. Crushed stone and gravel usually land around 1.3 to 1.5 tons per cubic yard, and wet or fine-packed material runs heavier. QtyLab defaults to 1.4. If your landscape yard quotes a different number for the exact product you are buying, use theirs — it is the number they will bill you on.
How much extra to order
- 10% for loose decorative gravel or pea gravel on a level, well-edged area.
- 15–20% for base material you will compact (crusher run, road base). It settles when tamped, so the same space takes more stone.
- Uneven ground: measure depth at several spots and use the average, or add a little more waste.
This is planning math, not a structural spec. For a driveway that will carry heavy trucks, ask your supplier or a local contractor what base depth they recommend for your soil.
Coverage chart by depth
How much area one cubic yard or one ton covers at common depths (1.4 tons/yd³, no waste added):
| Depth | Sq ft per cubic yard | Sq ft per ton | Typical use |
|---|---|---|---|
| 2 in | 162 | 116 | Top dressing, refresh an old path |
| 3 in | 108 | 77 | Walkways, decorative beds |
| 4 in | 81 | 58 | Driveway top layer, patio base |
| 6 in | 54 | 39 | Driveway base layer |
Common projects at a glance
All with 10% waste at 1.4 tons/yd³. Click any row to open the calculator with those numbers filled in.
| Project | Size | Depth | Cubic yards | Tons |
|---|---|---|---|---|
| Garden path | 4 × 20 ft | 3 in | 0.81 | 1.1 |
| Patio or shed base | 10 × 10 ft | 4 in | 1.36 | 1.9 |
| Single-car driveway | 12 × 20 ft | 4 in | 3.26 | 4.6 |
| Single-car driveway, thick base | 12 × 20 ft | 6 in | 4.89 | 6.8 |
| Long driveway | 12 × 50 ft | 4 in | 8.15 | 11.4 |
Doing a whole driveway? See how much gravel for a driveway for tons by driveway size, layer depths and how many truckloads to order.
Bags or bulk?
One cubic yard is 27 cubic feet, which is 54 bags of 0.5 cu ft gravel (a common bag size for pea gravel and landscape rock — check the label). Bags work for a small path or a planter. Past about one cubic yard, bulk delivery from a landscape yard is usually cheaper and saves you a lot of lifting. Many yards also have a minimum delivery, so ask before you order.
Common mistakes
- Forgetting to divide inches by 12. A 4-inch depth is 0.33 ft, not 4 ft.
- Ordering tons without checking density. The same cubic yards of a heavier stone weigh more tons.
- No extra for compaction. Base material settles; plan 15–20% more.
- Skipping edging. Without edging, gravel migrates into the lawn and you keep topping it up.
- Measuring only one spot. Dig test holes at a few points and average the depth.
Shopping list for a 12×20 driveway (4 in)
- About 4.6 tons (3.26 yd³) of crushed stone — order bulk from a local landscape yard; most people round up to 5 tons.
- About 270 sq ft of landscape fabric (240 sq ft plus overlap) — shop landscape fabric
- 1 hand tamper for edges, or rent a plate compactor for the main area — shop hand tampers
- 1 gravel or landscape rake — shop landscape rakes
- 1 wheelbarrow — shop wheelbarrows
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Pouring a slab on top? Use the concrete calculator for the slab, and see how many bags of concrete you need.
Laying a paver patio? The base gravel for it (with 20% extra for compaction), plus pavers and bedding sand, is worked out in how many pavers do I need, or run your size in the paver calculator.
Gravel FAQ
How many tons of gravel do I need for a 12×20 driveway?
At 4 inches deep with 10% waste, a 12×20 ft driveway needs about 3.26 cubic yards, or roughly 4.6 tons at 1.4 tons per cubic yard. Most people round up and order 5 tons.
How much area does a ton of gravel cover?
At 1.4 tons per cubic yard, one ton covers about 116 sq ft at 2 inches, 77 sq ft at 3 inches, 58 sq ft at 4 inches, and 39 sq ft at 6 inches. Heavier stone covers less.
How many bags of gravel are in a cubic yard?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cu ft gravel. Bags only make sense for small jobs; past about 1 cubic yard, bulk delivery is usually cheaper and less work.
How much extra gravel should I order?
Add about 10% for loose decorative gravel. For base material you will compact, such as crusher run, many people add 15–20% because it settles. The calculator lets you set your own waste factor.
How many cubic yards are in a ton of gravel?
About 0.71 cubic yards at 1.4 tons per yard. So 5 tons is about 3.6 yards, 10 tons about 7.1 yards, and 20 tons about 14.3 yards.