Quick answer: measure the area in feet, multiply length × width × depth (in feet), and divide by 27 to get cubic yards. To convert to tons, multiply cubic yards by the weight of your gravel per yard ÷ 2,000. Typical gravel weighs about 2,700 lb per cubic yard, so 1 cubic yard ≈ 1.35 tons. Add about 10% for compaction and uneven ground.
Want the answer in five seconds? Enter your measurements in the Gravel Calculator. It shows cubic yards, tons, and cost, and you can change the weight per yard to match your supplier. Keep reading to learn how the math works, how deep to go, and how to order without running short or paying for a truckload you can’t use.
The gravel formula
Cubic feet = length (ft) × width (ft) × depth (ft)
Cubic yards = cubic feet ÷ 27
Tons = cubic yards × weight per yd³ (lb) ÷ 2,000A cubic yard is 3 ft × 3 ft × 3 ft, which is 27 cubic feet. That is why you divide by 27 (see the NIST conversion factors). Depth trips people up most often because it’s measured in inches. Divide inches by 12 to get feet: 2 in = 0.167 ft, 3 in = 0.25 ft, 4 in = 0.333 ft, 6 in = 0.5 ft.
For weight, North Bay Materials lists sand, gravel, crushed rock and river cobble at 2,500–2,900 lb per cubic yard. The figure changes with the rock type, its size and how wet it is. CalcQuarry uses 2,700 lb (1.35 tons per yard) unless you enter something different. If your supplier gives you a weight, use theirs.
How to figure out how much gravel you need, step by step
- Measure length and width in feet. For an L-shaped or irregular area, divide it into rectangles, work out each one, then add them together. For a circle, area = 3.1416 × radius².
- Choose a depth. Use the depth the gravel should have after it is spread and compacted. See the depth guide below.
- Convert depth to feet (inches ÷ 12).
- Multiply and divide by 27 to get cubic yards.
- Convert to tons if your supplier sells by weight. Multiply by your weight per yard and divide by 2,000.
- Add an allowance. About 10% covers low spots and settling. Compacted base rock needs more (see ordering tips).
- Do the math once per layer. A driveway often has a coarse base and a finer top layer. Calculate each one on its own, because you’ll usually order them as different materials.
How deep should gravel be? Recommended depths by project
Depth matters more than anything else in your estimate. Going from 2 in to 4 in doubles the order. These ranges come from published standards. Soft clay, poor drainage and deep frost all mean going deeper.
| Project | Typical depth | Source / notes |
|---|---|---|
| Driveway base (crushed stone with fines) | At least 6 in compacted on well-drained soil. Add 2–4 in in cold climates or on wet or weak soil. | ICPI Tech Spec 2 (residential driveway base under pavers). CalcQuarry’s paver base calculator uses 8–12 in for driveways. |
| Patio base | At least 4 in compacted on well-drained soil | ICPI Tech Spec 2 (patios and pedestrian areas), plus about 1 in of bedding sand on top for pavers |
| Walkway / garden path base | At least 4 in compacted | ICPI Tech Spec 2 (sidewalks and pedestrian areas). Add a decorative top layer, such as pea gravel, on top of this. |
| Drainage (foundation drain / French drain) | At least 2 in of washed stone under the pipe and 6 in over it | International Residential Code Section R405.1 |
For drainage jobs, use clean (washed) stone so water can flow through it. For bases under driveways and pavers, use crushed stone that still has its fines (often sold as road base or crusher run), because it locks together when compacted. Names and sizes vary from quarry to quarry, so ask your supplier what they carry. The Crushed Stone Calculator handles base and drainage stone. For trenches, measure the stone depth from the trench bottom to where the stone stops, not to the top of the lawn.
Worked example 1: how much gravel do I need for my driveway?
Take a single-car driveway that is 12 ft wide and 50 ft long (600 ft²), built in two layers:
- Base, 6 in compacted crushed stone: 50 × 12 × 0.5 = 300 ft³ ÷ 27 = 11.11 yd³. At 2,700 lb/yd³: 11.11 × 2,700 ÷ 2,000 = 15 tons.
- Top layer, 2 in: 50 × 12 × 0.167 = 100 ft³ ÷ 27 = 3.70 yd³, or 5 tons.
- Add 10%: about 12.2 yd³ (16.5 tons) of base and 4.1 yd³ (5.5 tons) of top stone. That’s roughly 22 tons in total.
If you are only adding a 4 in top-up layer to an existing driveway the same size, it works out to 7.41 yd³, or about 10 tons (11 tons with 10% extra). Both quantities need a dump truck, not a pickup.
Worked example 2: a garden path
A path 3 ft wide, 40 ft long and 3 in deep: 40 × 3 × 0.25 = 30 ft³ ÷ 27 = 1.11 yd³, or about 1.5 tons (about 1.65 tons with 10% extra). If you want a soft, rounded surface for a path or play area, the Pea Gravel Calculator runs the same math for pea gravel. If the path needs a compacted base underneath, calculate that layer separately with the Paver Base Calculator.
Gravel coverage: how far does a cubic yard or a ton go?
Calculated at 2,700 lb per cubic yard (1 ton ≈ 0.74 yd³):
| Depth | Area per cubic yard | Area per ton | Tons per 100 ft² |
|---|---|---|---|
| 2 in | 162 ft² | 120 ft² | 0.83 tons |
| 3 in | 108 ft² | 80 ft² | 1.25 tons |
| 4 in | 81 ft² | 60 ft² | 1.67 tons |
Example: a 300 ft² patio area at 3 in deep needs 300 ÷ 108 ≈ 2.8 yd³, or about 3.75 tons. If your stone is heavier or lighter than 2,700 lb per yard, each ton covers a little less or a little more. Use the Cubic Yards to Tons Calculator with your supplier’s figure, or the Cubic Yard Calculator to get volume for any shape.
Ordering tips
- Allow for waste and compaction. Order about 10% extra for loose gravel. Crushed base rock loses about 10–20% of its loose volume once it’s compacted in layers, so order toward the high end for bases. Running short in the middle of a job usually means paying for a second delivery.
- Order in the unit your supplier uses. If they sell by the ton, ask what their material weighs per yard and convert with that number, not a generic figure.
- Bulk or bags? Bagged gravel is labeled in cubic feet. Divide your total cubic feet by the bag size to get the number of bags (a cubic yard is 27 ft³). Bags work for small jobs like the path above. For anything measured in tons, bulk delivery is usually simpler. Ask about delivery minimums and short-load fees before you decide.
- Plan the drop spot. A loaded dump truck is heavy, so have it tip as close to the work area as is safe, and keep it off septic systems and thin concrete.
- Order each layer separately. Base stone and top stone are different products, so get separate quotes for each.
Frequently asked questions
How much gravel do I need for a 10×10 area?
At 3 in deep: 10 × 10 × 0.25 = 25 ft³ ÷ 27 = 0.93 yd³, about 1.25 tons at 2,700 lb per yard. At 4 in deep it’s 1.23 yd³, about 1.67 tons.
How many tons of gravel do I need for a driveway?
Multiply length × width × depth in feet, divide by 27, then multiply by about 1.35 tons per yard. A 12 × 50 ft driveway at 4 in deep needs 7.41 yd³, about 10 tons. A two-layer build with a 6 in base and a 2 in top needs about 20 tons before the extra allowance.
How much does a cubic yard of gravel weigh?
Usually 2,500–2,900 lb, or about 1.35 tons, according to North Bay Materials. Wet or very dense stone can weigh more.
How many square feet does a ton of gravel cover?
About 120 ft² at 2 in deep, 80 ft² at 3 in, and 60 ft² at 4 in, assuming 2,700 lb per cubic yard.
Should I buy gravel by the ton or by the yard?
Buy in whichever unit your supplier prices in. Convert using their weight per yard so you’re comparing the same thing. The gravel calculator shows both units.
Ready to order? Enter your measurements in the Gravel Calculator to get cubic yards, tons and cost in one place.
Sources
- North Bay Materials, Landscape Material Density Chart: gravel weight per cubic yard.
- Interlocking Concrete Pavement Institute, Tech Spec 2: Construction of Interlocking Concrete Pavements: minimum base thicknesses.
- International Code Council, 2021 IRC Section R405.1: foundation drain stone requirements.
- NIST, SP 811 Appendix B: unit conversions.