How many tons of gravel do I need? It is a deceptively simple question, and the reason people get stuck is that gravel is ordered two different ways. You measure the hole or the area in volume (cubic yards), but many suppliers sell and price by weight (tons). To go from one to the other you need a density figure. This guide walks through the full path: area to cubic feet, cubic feet to cubic yards, and cubic yards to tons, with real numbers and worked examples you can copy for your own project.
The short answer
First find the volume in cubic yards, then multiply by roughly 1.4 to get tons. For a typical 20 ft x 40 ft driveway at 4 inches deep that works out to about 10 cubic yards, or roughly 14 tons of gravel. The exact weight depends on the type of gravel, so treat the tonnage as an estimate and order a little extra.
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Step 1: Find the volume in cubic feet
Everything starts with volume. The formula is length times width times depth, all measured in feet:
volume (cubic feet) = length (ft) x width (ft) x depth (ft)
The catch is depth. You almost always want gravel a few inches deep, not a few feet, so you have to convert inches to feet by dividing by 12. A few common depths:
- 2 inches = 0.167 ft
- 3 inches = 0.25 ft
- 4 inches = 0.333 ft
- 6 inches = 0.5 ft
Worked example: a patio area that is 10 ft long by 12 ft wide, filled 3 inches deep. The depth of 3 inches is 0.25 ft, so the volume is 10 x 12 x 0.25 = 30 cubic feet.
Step 2: Convert cubic feet to cubic yards
Gravel is sold and delivered by the cubic yard, not the cubic foot. Since a cubic yard is 3 ft on each side, one cubic yard equals 3 x 3 x 3 = 27 cubic feet. To convert, divide your cubic feet by 27:
cubic yards = cubic feet / 27
Continuing the patio example: 30 / 27 = 1.11 cubic yards. That is the amount of gravel by volume. Most yards let you order in fractions or round up to the next quarter yard.
Step 3: Convert cubic yards to tons
This is the step that trips people up. To turn volume into weight you multiply by the material density, expressed in tons per cubic yard. Gravel density varies by type, moisture, and how tightly it is packed, but a common working average is about 1.4 tons per cubic yard (most gravels land in the 1.4 to 1.5 range):
tons = cubic yards x 1.4
For the patio: 1.11 x 1.4 = 1.55 tons. Round up and order 1.5 to 2 tons to be safe. Remember this is an estimate. Some suppliers sell strictly by the ton, others by the cubic yard, so knowing both numbers lets you order confidently either way and check that a quote is fair.
Density is not universal
Weight by material type
Not everything you might spread weighs the same. Here are approximate densities for common landscaping materials so you can swap the multiplier to match what you are actually ordering. All figures are rough averages for dry material.
| Approx. tons per cubic yard | Notes | |
|---|---|---|
| Pea gravel | ~1.4 | Rounded, drains well |
| Crushed stone (#57) | ~1.4 | Angular, common base rock |
| River rock | ~1.4 | Decorative, larger stones |
| Sand | ~1.35 | Fills gaps, packs tight |
| Topsoil | ~1.1 | Lighter, varies with moisture |
As a rule of thumb, most stone products cluster near 1.4 tons per cubic yard, sand runs slightly lighter, and topsoil is lighter still. When in doubt, ask the supplier for the exact density of the product on your ticket.
How deep should gravel be?
Depth drives both the volume and the final tonnage, so getting it right matters more than any other input. Recommended depths by use:
- Walkway or a top decorative layer: 2 to 3 inches
- Patio base under pavers or slabs: about 4 inches
- Driveway: multiple layers totaling roughly 8 to 12 inches (a coarse base plus a finer surface)
A driveway is the big one. You do not pour a single 4 inch layer and call it done. A durable gravel driveway is built up in lifts: a larger crushed stone base for drainage and load, then one or two finer layers on top. Because of that, driveway tonnage adds up fast, so plan the full depth before you order.
Full worked example: a gravel driveway
Say your driveway is 20 ft wide by 40 ft long and you want a 4 inch surface layer. Walk it through the three steps:
- Area: 20 x 40 = 800 square feet
- Volume: 800 x 0.333 ft (4 inches) = ~267 cubic feet
- Cubic yards: 267 / 27 = ~9.9 cubic yards
- Tons: 9.9 x 1.4 = ~14 tons
So a 4 inch surface layer on that driveway is close to 10 cubic yards, or about 14 tons. If you are also building the base, repeat the calculation for each layer and add them together. A full 8 to 12 inch driveway build could easily require two to three times this amount.
Coverage: how far does one cubic yard go?
Sometimes it is easier to think in terms of coverage. One cubic yard spread at a given depth covers a fixed area. Since a cubic yard is 27 cubic feet, at 1 inch (0.0833 ft) deep it covers about 324 square feet, and the area halves as you double the depth.
| Depth | Area covered by 1 cubic yard | |
|---|---|---|
| 1 inch deep | 1 inch | ~324 sq ft |
| 2 inches deep | 2 inches | ~162 sq ft |
| 3 inches deep | 3 inches | ~108 sq ft |
| 4 inches deep | 4 inches | ~81 sq ft |
To use this table, divide your total square footage by the coverage figure for your chosen depth. For example, 800 sq ft at 4 inches is 800 / 81 = ~9.9 cubic yards, which matches the driveway math above.
Order about 10 percent extra
Common questions
How many tons is a cubic yard of gravel?
About 1.4 tons for a typical gravel, and often quoted in the 1.4 to 1.5 range. Multiply your cubic yards by 1.4 for a solid estimate, or use your supplier's stated density if they give one.
How much gravel do I need for a driveway?
For a 20 ft x 40 ft driveway with a 4 inch layer, roughly 10 cubic yards or about 14 tons. A full driveway build with a base plus surface (8 to 12 inches total) needs several times that, so calculate each layer and add them up.
How deep should gravel be?
2 to 3 inches for a walkway or decorative top layer, about 4 inches for a patio base, and 8 to 12 inches of combined layers for a driveway. Deeper is not always better, but too shallow lets the ground show through and rut.
How much does a ton of gravel cover?
A ton is roughly 0.7 cubic yards (since about 1.4 tons make a cubic yard). At 2 inches deep, one ton covers around 110 to 120 square feet. At 4 inches deep it covers about 55 to 60 square feet. Coverage drops as depth increases.
Should I order by the ton or the cubic yard?
Either works as long as you know the conversion. Cubic yards match how you measured the space, while tons match how many suppliers price and weigh a delivery. Calculate both so you can compare quotes and confirm you are getting the volume you expect.