How to use the gravel calculator
- Measure the area. Use length × width for rectangles, the diameter for round areas, or type the square footage directly if you already know it. Split an L-shaped or curved driveway into rectangles, run each one, and add the results.
- Set the depth in inches (or centimeters). This is the finished thickness of the layer, not the depth of the hole — if you excavate 6 in and plan 2 in of sand on top, enter 4 in for the gravel.
- Pick the material. Each one uses a typical weight per cubic yard. If your supplier quotes a different figure, choose Other and type it in — it changes the tonnage directly.
- Keep an allowance for compaction and waste. Some stone always ends up pressed into the soil or left on the tarp.
Quarries and landscape yards sell gravel either by the ton or by the cubic yard, so the calculator gives both. Ask which unit your supplier uses and enter the matching price.
The gravel formula
Cubic yards = cubic feet ÷ 27
Tons = cubic yards × tons per cubic yard
Dividing the depth by 12 turns inches into feet, so the result is in cubic feet. There are 27 cubic feet in a cubic yard (3 × 3 × 3). The last step converts volume to weight using the material's density — which is where most of the uncertainty lies, because stone size, shape and moisture all change how much a yard weighs.
Worked example: a 20 × 10 ft patio base
A 20 × 10 ft area is 200 sq ft. At 4 in of crushed stone: 200 × 4 ÷ 12 = 66.7 cubic feet. Adding 10% gives 73.3 cubic feet, or 73.3 ÷ 27 = 2.72 cubic yards. At 1.4 tons per cubic yard, that's 2.72 × 1.4 = 3.80 tons.
In half-cubic-foot bags it would take 147 bags — which is why anything bigger than a small path is usually cheaper and far less work to have delivered in bulk.
Typical gravel weights and uses
These are commonly published loose (uncompacted) weights. Real figures vary by quarry, rock type and moisture, so check with your supplier, especially for large orders.
| Material | Typical size | Tons per cu yd | Common uses |
|---|---|---|---|
| Crushed stone (#57) | About ½–1 in, angular | 1.4 | Drainage, driveway layers, slab and shed bases |
| Pea gravel | About ⅜ in, rounded | 1.4 | Paths, play areas, between stepping stones |
| River rock | 1–3 in or larger, rounded | 1.35 | Decorative beds, dry creek beds |
| Crusher run / road base | ¾ in stone mixed with fines | 1.5 | Driveways, compacted base under pavers and sheds |
| Decomposed granite | ¼ in and smaller | 1.35 | Paths and patios that pack firm |
| Sand (dry) | Fine | 1.35 | Paver bedding, leveling, fill |
A cubic yard covers 162 sq ft at 2 in deep, 108 sq ft at 3 in and 81 sq ft at 4 in. At 1.4 tons per yard, one ton covers about 116 sq ft at 2 in, 77 sq ft at 3 in or 58 sq ft at 4 in.
How deep should gravel be?
| Project | Typical depth |
|---|---|
| Garden path or walkway | 2–3 in of pea gravel or decomposed granite, ideally over a compacted base |
| Decorative ground cover | 2–3 in |
| New gravel driveway | 8–12 in in total, built in layers with coarse stone at the bottom |
| Resurfacing a driveway | 2–4 in on top of the existing base |
| Base under pavers (patio, walk) | 4–6 in compacted, plus about 1 in of bedding sand |
| Base under pavers (driveway) | Compacted: 6 in (15 cm) minimum on firm, well-drained soil; 8–12 in (20–30 cm) on clay, poorly drained or frost-prone soil. Plus about 1 in of bedding sand |
| Under a concrete slab or shed | 4 in compacted is a common minimum |
| French drain | 2–3 in of washed stone under the pipe, then fill the trench around and over it |
Poorly drained clay and heavy vehicles call for the deeper end of each range. For paver projects, use the paver calculator to count the pavers; for slabs, the concrete calculator handles the pour itself.
Compaction: why you need extra
Angular, dense-graded materials such as crusher run, road base and decomposed granite contain fines that fill the gaps between stones. When you run a plate compactor over them, the layer gets noticeably thinner, so contractors commonly order 15–20% extra for a compacted base. Clean stone like #57 and rounded pea gravel barely compact, so 5–10% for spreading losses is usually enough. Compact in layers a few inches thick rather than all at once — a compactor can't consolidate a deep layer from the top.
Ordering tips
- Confirm the unit. A price per ton and a price per yard are not interchangeable. Enter whichever your supplier quotes and the calculator does the conversion.
- Round up. Many yards sell in half-ton or half-yard steps. A small shortfall means a second delivery charge.
- Plan the drop spot. A loaded dump truck is heavy enough to crack a concrete driveway or rut a lawn. Put down a tarp where the pile will land to make cleanup easier.
- Use landscape fabric or geotextile between soil and stone on driveways and paths. It keeps the gravel from sinking into the soil.
Frequently asked questions
How many tons of gravel are in a cubic yard?
Most gravel and crushed stone weighs about 1.3–1.5 tons per cubic yard; 1.4 tons is a common figure for #57 stone and pea gravel. Dense road base runs heavier and wet material weighs more, so ask your supplier for their number.
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 deep, 77 sq ft at 3 inches, or 58 sq ft at 4 inches.
How much gravel do I need for a 10 × 20 area?
At 4 inches deep, 200 sq ft needs 66.7 cubic feet, or 2.47 cubic yards — about 3.5 tons of crushed stone. With 10% extra, order about 2.7 cubic yards or 3.8 tons.
What gravel is best for a driveway?
Use angular stone that locks together. A common build is coarse crushed stone at the bottom and crusher run or #57 stone on top. Avoid pea gravel and river rock on driveways because the rounded stones roll and rut.
Do I need landscape fabric under gravel?
It's strongly recommended for driveways and paths. A woven geotextile keeps the stone from mixing into the soil underneath, so the layer stays thick and firm for longer.