To work out how much gravel you need, multiply the area by the depth to get the volume, then convert that volume to cubic yards or tons, whichever unit your supplier sells by.
Quick answer: square feet × depth in inches ÷ 324 = cubic yards. Multiply cubic yards by about 1.4 to estimate tons of crushed stone. For example, 100 sq ft at 3 inches deep is about 0.93 cubic yards, or roughly 1.3 tons.
Want the answer without the math? The Gravel Calculator does every step below for crushed stone, pea gravel, river rock and crusher run.
How to calculate how much gravel you need
- Measure the area. For a rectangle, multiply length × width in feet. For an irregular area, split it into rectangles and circles, work out each one, and add them together.
- Choose the depth. Decide how many inches of gravel the project needs (see the depth section below).
- Convert to cubic feet. Area × (depth in inches ÷ 12) = cubic feet.
- Convert to cubic yards. Cubic feet ÷ 27 = cubic yards. Or use the shortcut: square feet × depth in inches ÷ 324.
- Convert to tons if needed. Cubic yards × the gravel’s weight per cubic yard = tons.
- Add a little extra. An allowance for uneven ground, settling and spillage helps you avoid running short.
The 324 in the shortcut comes from 12 inches per foot × 27 cubic feet per cubic yard. It’s the same conversion explained in square feet to cubic yards.
Gravel needed per 100 square feet
This chart uses 1.40 US tons per cubic yard, a common planning figure for crushed stone. For a different area, scale it: 500 sq ft needs five times these amounts.
| Depth | Cubic yards per 100 sq ft | Tons per 100 sq ft (at 1.40 t/yd³) |
|---|---|---|
| 2 inches | 0.62 | 0.86 |
| 3 inches | 0.93 | 1.30 |
| 4 inches | 1.23 | 1.73 |
| 6 inches | 1.85 | 2.59 |
Lighter gravel such as pea gravel (about 1.35 tons per cubic yard in our calculator) needs the same cubic yards but slightly fewer tons.
How many tons are in a cubic yard of gravel?
It depends on the stone. Published figures for loose decorative and drainage gravel are commonly quoted between about 1.2 and 1.5 US tons per cubic yard, depending on the rock type, stone size and shape, and moisture. Crusher run and road base, which contain fines that fill the gaps between stones, are often heavier, especially once compacted. For weights by gravel type and ton-to-yard conversion tables, see how much does a yard of gravel weigh.
If you’re buying by the cubic yard, the weight doesn’t change how much you order. If you’re buying by the ton, ask your supplier which weight they use for their gravel, since it changes how many cubic yards you actually receive.
How deep should gravel be?
Many paths, patios and decorative beds use about 2–4 inches of gravel. Larger stones such as river rock usually need a deeper layer to cover the ground fully.
Driveways are different. They’re normally built in layers: a compacted base of larger or dense-graded stone, then a surface layer on top. Recommended total depths vary a lot between suppliers and contractors, from around 4–6 inches for a light-use driveway on firm soil to 8–12 inches or more for heavier vehicles or soft ground. Ask a local supplier or contractor what works for your soil and traffic, then calculate each layer separately.
Putting gravel under pavers? That base follows its own guidelines; see paver base depth.
Worked examples
A pea gravel path
A path 3 ft wide and 40 ft long, 3 inches deep: 3 × 40 = 120 sq ft. 120 × 3 ÷ 324 = 1.11 cubic yards (30 cubic feet). At 1.35 tons per cubic yard, that’s about 1.50 tons. In 0.5 cu ft bags, it would take 60 bags.
A 10 × 12 shed pad
At 4 inches deep: 10 × 12 = 120 sq ft. 120 × 4 ÷ 324 = 1.48 cubic yards. At 1.40 tons per cubic yard, that’s about 2.07 tons of crushed stone. Check the shed manufacturer’s foundation instructions for the depth and base they recommend.
1,000 square feet of gravel
At 3 inches deep: 1,000 × 3 ÷ 324 = 9.26 cubic yards, or about 12.96 tons at 1.40 tons per cubic yard. At 2 inches it’s 6.17 cubic yards (about 8.64 tons), and at 4 inches it’s 12.35 cubic yards (about 17.28 tons).
A driveway built in two layers
As an example only, take a driveway 12 ft wide and 50 ft long (600 sq ft) with a 4-inch base and a 2-inch surface layer. Work out each layer on its own:
- Base: 600 × 4 ÷ 324 = 7.41 cubic yards. At 1.50 tons per cubic yard (loose crusher run), about 11.11 tons.
- Surface: 600 × 2 ÷ 324 = 3.70 cubic yards. At 1.40 tons per cubic yard (crushed stone), about 5.19 tons.
That’s about 11.11 cubic yards or 16.30 tons in total. Because crusher run compacts when it’s tamped, a compacted base needs more material than its loose volume suggests, so ask your supplier how much extra to allow.
Bagged gravel or bulk delivery?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cu ft to make one cubic yard. Bags are handy for small jobs and touch-ups, but for anything around a cubic yard or more, bulk delivery is usually far less work. Compare a bulk quote with the bag price before you decide.
Getting it home
Gravel is heavy. At 1.2–1.5 tons per cubic yard, a single cubic yard weighs roughly 2,400–3,000 lb, which is more than many light-duty pickups are rated to carry. Check the payload rating on your vehicle’s door-jamb sticker before hauling it yourself. Delivery truck capacity varies by truck, so ask your supplier how much they can bring in one load.
Common mistakes
- Mixing units, such as multiplying square feet by inches without dividing by 12.
- Treating cubic yards and tons as the same thing.
- Using one depth for a whole driveway instead of calculating each layer.
- Forgetting that crusher run compacts and needs extra material.
- Ordering exactly the calculated amount with no allowance for uneven ground.
FAQ
How many tons of gravel do I need for 1,000 square feet?
About 8.6 tons at 2 inches, 13 tons at 3 inches, or 17.3 tons at 4 inches, using 1.40 tons per cubic yard. Lighter or heavier gravel changes the tonnage, not the cubic yards.
How much area does a ton of gravel cover?
At 1.40 tons per cubic yard, one ton is about 19.3 cubic feet, which covers roughly 115 sq ft at 2 inches, 77 sq ft at 3 inches, or 58 sq ft at 4 inches.
Should I order gravel by the ton or the yard?
Order in whichever unit your supplier quotes. If they sell by the ton, use their weight per cubic yard to convert, since it varies between products.
How much extra gravel should I order?
A small allowance, often 5–10%, helps cover uneven ground and spillage. Compactable base materials like crusher run may need more; your supplier can advise.
Bottom line
Square feet × depth in inches ÷ 324 gives you cubic yards; multiply by the gravel’s weight per cubic yard (about 1.4 for crushed stone) to get tons. Choose your depth for the job, calculate driveway layers separately, and add a small allowance. To skip the math, use the Gravel Calculator, or the Cubic Yards Calculator for soil, mulch and sand.
Gravel weights here are planning estimates and vary by stone, moisture and supplier. Confirm weights, depths and delivery details with your supplier before ordering.