Gravel calculator
Gravel is ordered in cubic yards and delivered by the ton, and the two only agree if you know the density of the specific stone. Get the volume right and the tonnage follows; get the depth wrong and nothing downstream can fix it.
Area and depth
How this is calculated
- Volume in cubic feet = length × width × (depth ÷ 12).
- With waste = volume × (1 + allowance).
- Cubic yards = cubic feet ÷ 27.
- Tons = cubic yards × density. Density is the loose bulk density of the stone, which is why the type selector changes the tonnage but not the volume.
A cubic yard is 27 cubic feet. It covers 324 sq ft at 1 inch, 108 sq ft at 3 inches, 81 sq ft at 4 inches and 54 sq ft at 6 inches. Those four numbers answer most gravel questions without touching the calculator.
Worked example
A 20 × 10 ft pad at 4 inches of 3/4″ crushed stone, 10% waste:
- Area = 20 × 10 = 200 sq ft
- Volume = 200 × (4 ÷ 12) = 66.7 cu ft
- With waste = 66.7 × 1.10 = 73.3 cu ft
- Cubic yards = 73.3 ÷ 27 = 2.72 cu yd
- Tons = 2.72 × 1.40 = 3.80 tons
Order 3 cubic yards, or 4 tons if the yard only sells by weight. The difference between 2.72 and 3 is not rounding error — bulk suppliers sell in half-yard increments at best, and a partial yard costs nearly the same as a full one.
Depth by use
| Application | Compacted depth | Note |
|---|---|---|
| Footpath, pedestrian only | 2″ | Over a geotextile, or the stone sinks. |
| Patio base under pavers | 4″ | Plus 1″ of bedding sand. |
| Residential driveway | 4–6″ | 6″ over soft subgrade. |
| Drainage bed behind a wall | 12″ | Width matters more than depth here. |
| Decorative bed, no traffic | 2″ | Pea gravel migrates; use angular stone. |
Loose aggregate places roughly 20% deeper than the finished layer because it compacts under traffic and water. A 4-inch compacted layer goes down at about 5 inches loose. The calculator works in compacted depth, so do not add that 20% on top of the waste allowance.
Where the tonnage stops being accurate
- It does not size a driveway for vehicles. Axle loads need a base thickness derived from subgrade strength, which is a soils question, not an arithmetic one.
- It does not account for a geotextile. A separation fabric typically saves an inch of stone over soft ground and prevents the stone from migrating into the soil.
- It does not convert to bags. Bagged gravel is sold at a different density and a wildly different price; buy bulk above about half a yard.
- The densities are typical, not certified. Quarried stone varies by source. If the invoice is by weight, ask the yard for their figure and expect it within about 5% of the values here.
Questions people actually ask
Questions people actually ask
How many cubic yards is a ton of gravel?
About 0.71 cubic yards per ton for 3/4″ crushed stone at 1.40 tons per cubic yard. That is 1 ÷ 1.40. Pea gravel is closer to 0.74 and crusher run closer to 0.67, so the answer depends on the stone.
How much does a cubic yard of gravel weigh?
Roughly 2,800 lb for 3/4″ crushed stone, 2,700 lb for pea gravel and 3,000 lb for crusher run. A pick-up truck rated at half a ton should not carry a full yard.
Do I order by the yard or the ton?
Price both. Yards are volume and do not change with moisture; tons are weight and do. If the quote is by the ton and the stone has been rained on, you are paying for water.
How deep should gravel be for a shed base?
Four inches of compacted 3/4″ crushed stone over a geotextile, in two 2-inch lifts, is the common minimum for a light shed. A loaded shed or a vehicle pad needs more and needs the subgrade assessed.