Gravel / Base Calculator
Estimate the gravel for a driveway, walkway base, or fill. Enter the area and depth, choose a material, and the calculator returns the cubic yards to place — including a labeled compaction allowance — and the tonnage to order. Tonnage shows in US short tons or, in metric mode, metric tonnes.
Calculate
Default result: 2.72 yd³
Result
Volume (includes compaction)
- Tonnage
- 3.8 tons
How to calculate
Enter the length and width of the area and the depth of the gravel layer (depth is in inches or centimeters). Add a compaction allowance so the compacted base ends up at full depth, pick the closest material, and adjust the density if your supplier lists a different value. The volume is the big number; the tonnage row tells you how much to order by weight.
yd³ = (length × width × depth) ÷ 27 × (1 + compaction / 100), with all dimensions in feet. tons = yd³ × density, where density is in US short tons per cubic yard (default 1.4). In metric mode the same volume is shown in cubic meters and the tonnage in metric tonnes.
Example calculation
A 20 ft by 10 ft area at 4 inches deep is (20 × 10 × 4 ÷ 12) ÷ 27 = 2.47 cubic yards. Adding a 10% compaction allowance gives about 2.72 cubic yards. At a density of 1.4 short tons per cubic yard that is roughly 3.8 tons of gravel to order.
- volume
- 2.72 yd³
- massKg
- 3.8 tons
Assumptions
- Density defaults to 1.4 US short tons per cubic yard. Gravel ranges from about 1.4 to 1.7 tons/yd³ depending on the material — pea gravel and crushed stone are near 1.4, road base near 1.5. The material select documents typical values; the density field is editable so you can match your supplier.
- The compaction allowance defaults to 10% and is shown as a separate, labeled input — never baked in silently. Compacted base loses volume, so 10–15% extra is typical. Not all gravel is compacted; set the allowance to 0 for loose fill or decorative gravel.
- The depth field uses a thickness unit (inches or centimeters) that is separate from the length and width units (feet or meters), because gravel layers are thin.
- Tonnage assumes the density you entered. Because suppliers sell gravel by weight, the tonnage figure is the one to order against; the cubic-yard figure tells you how much you are placing.
- Results are estimates for planning. Confirm density and coverage with your supplier and round up for delivery.
Common mistakes
- Forgetting the compaction allowance. A base placed loose and then compacted ends up shallower than planned, so most jobs order 10–15% extra material.
- Using the wrong density. Heavier crushed stone or road base weighs more per cubic yard than pea gravel, so using 1.4 for a denser material under-orders the tonnage.
- Mixing up depth units. Depth is entered in inches (or centimeters), not feet — entering 4 feet instead of 4 inches overstates the gravel twelvefold.
- Ordering by volume when the supplier sells by weight. Use the tonnage row for the order and the cubic-yard figure to check the placed volume.
Frequently asked questions
How many tons of gravel are in a cubic yard?
About 1.4 to 1.7 short tons, depending on the material. Pea gravel and crushed stone are near 1.4 tons per cubic yard; denser road base is closer to 1.5. The calculator uses 1.4 by default and lets you edit it.
Why does the calculator add a compaction allowance?
Gravel placed loose loses volume when it is compacted, so the finished base would be shallower than planned. The allowance — shown as a separate, labeled input — adds extra material so the compacted layer reaches full depth. Set it to 0 for loose or decorative gravel.
Should I order gravel by the ton or by the cubic yard?
Suppliers usually sell by weight, so order against the tonnage figure. The cubic-yard figure tells you how much you are placing and is useful for checking depth and coverage.
Why is depth entered in inches instead of feet?
Gravel layers are thin — typically a few inches — so the depth field uses inches (or centimeters in metric mode) to avoid mistakes, while the area uses feet or meters.