Gravel Calculator
Order 8 tons of Crushed stone (#57, ¾").
| Figure | Exact | With 10% waste |
|---|---|---|
| Volume | 4.94 yd³ | 5.43 yd³ |
| Weight | 6.91 tons | 7.6 tons |
| What to buy (whole tons) | 8 tons | |
Calculated at 2,800 lb per cubic yard (1.4 US short tons per yd³, about 1,661 kg/m³) for crushed stone (#57, ¾"). Real bulk density varies roughly ±10% with moisture, gradation, and how tightly the load is packed — ask your supplier for their figure on a large order. Aggregate is sold by the ton, so the "what to buy" row rounds up to the next whole ton.
Enter your area and depth to find how much gravel you need in tons and cubic yards — with a waste factor, a whole-ton order figure, and the cost.
How to use this calculator
- Pick imperial or metric. Imperial takes feet for length and width and inches for depth; metric takes metres and centimetres.
- Choose the shape of the area — rectangle for a driveway, path, or pad; circle for a fire pit surround or a round bed. For an irregular area, break it into rectangles and add the results.
- Enter the dimensions and depth. Depth is the finished thickness of the gravel layer, not the depth of the hole you dug.
- Select your material. This sets the density used to convert volume into tons, and the hint next to the depth field updates to the typical installed depth for that material.
- Adjust the waste factor if your site is uneven, and add a price per ton if you want the cost. Both are optional — 10% waste is already the default.
The formula
Cubic feet = Area (ft²) × (Depth (in) ÷ 12) · Cubic yards = Cubic feet ÷ 27 · Tons = Cubic yards × Density (tons/yd³)
Order quantity = Tons × (1 + waste ÷ 100), rounded up to the next whole ton · Cost = Order tons × Price per ton
Worked example — a 20 × 20 ft driveway
You are laying 4 inches of #57 crushed stone over a 20 ft × 20 ft parking pad, at the standard 10% waste factor.
- Area: 20 × 20 = 400 ft²
- Convert depth: 4 ÷ 12 = 0.333 ft
- Cubic feet: 400 × 0.333 = 133.3 ft³
- Cubic yards: 133.3 ÷ 27 = 4.94 yd³
- Tons: 4.94 × 1.4 = 6.91 tons
- With 10% waste: 6.91 × 1.10 = 7.60 tons
- What to order: 8 tons — suppliers sell by the whole ton
At a typical delivered price of $45 per ton that is about $360. Note how much the depth drives the total: dropping to 3 inches cuts the order to 6 tons, and going to 6 inches pushes it to 12.
How deep should the gravel be?
Depth is the single input people get wrong most often, and it moves the total more than anything else — the volume is directly proportional to it. These are the depths that hold up in practice:
| Application | Depth | Typical material |
|---|---|---|
| Decorative bed or border | 2 in | River rock, marble chips, lava rock |
| Garden path or walkway | 2–3 in | Pea gravel, decomposed granite |
| Residential driveway (top layer) | 4 in | #57 crushed stone |
| Driveway base layer | 4–6 in | Crusher run / road base |
| Heavy vehicle or RV pad | 6–8 in, in two layers | Crusher run base + #57 top |
| Paver or shed foundation base | 4–6 in compacted | Crusher run |
A driveway built in two layers is not the same as one deep layer. The coarse base carries the load and drains; the finer top layer gives you a surface that is comfortable to walk and drive on. If you are building both, run this calculator twice — once per layer — and add the tonnages.
Why the waste factor matters more here than you would think
The volume formula assumes a flat-bottomed box. A real excavation is not one. The subgrade has soft spots that swallow material, the edges of an unbordered area spread outward under the first rain, and the load compacts by several percent the first time anything drives over it. None of that shows up in length × width × depth.
10% is the right allowance for a prepared, bordered, reasonably level area. Push it to 15% when the subgrade is soft or uneven, when there is no edging to hold the material in, or when the area has a lot of perimeter relative to its size — a long narrow path loses proportionally more to spread than a square pad does.
Running short is the expensive failure. A second delivery costs another trip charge for a fraction of a load, and a driveway topped up weeks later never quite matches. Ordering 10% long costs you a few dollars of stone you can spread thinner or stockpile.
Coverage per ton, at a glance
Useful when the supplier quotes tonnage and you want to sanity-check the area it will actually cover. These figures are for typical crushed stone at 1.4 tons per cubic yard:
| Depth | Coverage per ton | Tons per 100 ft² |
|---|---|---|
| 1 in | ≈ 231 ft² | 0.43 tons |
| 2 in | ≈ 116 ft² | 0.86 tons |
| 3 in | ≈ 77 ft² | 1.30 tons |
| 4 in | ≈ 58 ft² | 1.73 tons |
| 6 in | ≈ 39 ft² | 2.59 tons |
Common mistakes to avoid
- Entering depth in feet. Depth is in inches. Typing 4 when you mean 4 inches is correct here; typing 0.33 gives you a third of an inch of gravel. The calculator rejects depths over 120 inches for exactly this reason.
- Confusing tons with cubic yards. They are not interchangeable — one cubic yard of crushed stone is about 1.4 tons. Suppliers quote tons; your tape measure gives you yards. Getting this backwards means ordering 40% too little or too much.
- Measuring the hole instead of the layer. If you excavated 8 inches and want 4 inches of gravel with 4 inches of soil replaced on top, enter 4, not 8.
- Assuming every material weighs the same. Lava rock is less than half the weight of crusher run for the same volume. If you switch material after ordering, the tonnage changes even though the volume did not.
- Forgetting compaction. Crusher run compacts noticeably — the finished depth after rolling is less than the loose depth you spread. The waste factor absorbs some of this, but for a base layer that must hit a specific finished depth, plan on spreading about 20% deeper than the target.
How we calculate this
Volume is area × depth. For a rectangle the area is length × width; for a circle it is π × (diameter ÷ 2)². Depth is converted from inches to feet before multiplying, and the result is divided by 27 to reach cubic yards. Weight is volume × the material's bulk density — 2,800 lb/yd³ (1.4 US short tons) for crushed stone and pea gravel, 3,000 lb/yd³ for crusher run and decomposed granite, down to 1,300 lb/yd³ for lava rock. The waste factor is applied to the volume, so it carries through to both the tonnage and the cost. The order figure rounds up to the next whole ton because that is the increment suppliers deliver in. All arithmetic is done in metric internally and converted once for display, which is why switching between imperial and metric produces the same answer rather than a slightly drifted one.
Sources
Frequently asked questions
How much gravel do I need for a 20x20 driveway?
A 20 ft × 20 ft area is 400 square feet. At the usual 4-inch depth that is 133 cubic feet, or 4.94 cubic yards. Most crushed stone weighs about 1.4 tons per cubic yard, so you need roughly 6.9 tons. Add the standard 10% waste factor and you should order about 7.6 tons — so 8 tons, since aggregate is sold by the whole ton.
How many tons of gravel are in a cubic yard?
About 1.4 tons for most crushed stone and pea gravel, which weigh roughly 2,800 lb per cubic yard. Denser materials run higher: crusher run and decomposed granite are closer to 1.5 tons per yard (3,000 lb). Lighter decorative materials run lower — lava rock is only about 0.65 tons per yard. This calculator uses the density of whichever material you pick and shows the figure it used.
How deep should gravel be?
For a walkway or decorative bed, 2 inches is enough. For a residential driveway, use 4 inches of gravel over a compacted base; if trucks or RVs will drive on it, go to 6 inches or build it in two layers with a coarser base beneath. Under a paver or shed foundation, 4 to 6 inches of compacted crusher run is typical. Deeper is not always better — depth without compaction just produces a soft surface that rutts.
Should gravel be ordered by the ton or by the yard?
In the US, aggregate is almost always sold and delivered by the ton, while the volume you actually measured is in cubic yards. That is the conversion this calculator does for you. Some landscape suppliers quote decorative stone by the yard or by the bag — if yours does, use the cubic yard figure instead. Both are shown.
How much does a ton of gravel cover?
At 2 inches deep, one ton of typical crushed stone covers about 116 square feet. At 3 inches it covers about 77 square feet, and at 4 inches about 58 square feet. Coverage halves as you double the depth, which is why depth matters far more than area when a delivery comes in short.
Why add a waste factor to a gravel order?
Because the calculated volume assumes a perfectly flat, perfectly excavated area, and no site is. Gravel settles into soft spots and tire ruts, spreads past the edges of an unbordered area, and compacts by several percent as it is rolled. 10% is the standard allowance for a prepared, bordered area. Use 15% for an uneven site, a soft subgrade, or an area with no edging to hold the material.
How much does a truckload of gravel hold?
A standard tandem-axle dump truck carries roughly 12 to 15 tons, or about 8 to 10 cubic yards. A smaller single-axle truck carries 5 to 7 tons. Because delivery is charged per trip, ordering just over a truckload is expensive — if your total lands slightly above one truck's capacity, it is usually worth adjusting the depth slightly rather than paying for a second trip.
What is the difference between crushed stone and pea gravel?
Crushed stone is mechanically broken, so the pieces have sharp angular faces that lock together and stay put — that is what you want for a driveway or a base layer. Pea gravel is naturally rounded river stone, which is comfortable underfoot and looks better in a garden bed but rolls and migrates under traffic. Both weigh about the same, around 1.4 tons per cubic yard, so the volume math is identical; the choice is about behaviour, not weight.