Quick answer
Driveway gravel starts with area × installed depth
For a rectangular driveway, multiply length by width by the installed gravel depth after converting all dimensions to one unit. Apply a visible allowance only when the project needs it. Convert volume to mass using a bulk density that matches the exact aggregate and its loose or compacted state.
Calculate my gravel nowThe formula
Calculate volume, tons, and bags
length × width × installed depthOrder volumenet volume × (1 + allowance ÷ 100)Estimated massorder volume × selected bulk densityComplete bagsround up (estimated mass ÷ bag weight)When using feet and inches, divide depth in inches by 12 before multiplying. Divide cubic feet by 27 to report cubic yards. Keep the unrounded volume for later steps.
Reference table
Net gravel volume for 100 ft²
These geometric values exclude allowance, compaction, and density.
| Depth | Cubic feet | Cubic yards |
|---|---|---|
| 2 in | 16.667 | 0.617 |
| 3 in | 25.000 | 0.926 |
| 4 in | 33.333 | 1.235 |
| 6 in | 50.000 | 1.852 |
Uneven excavation, slopes, settlement, and field compaction can make the installed project differ from a rectangular planning model.
Material input
One cubic yard does not have one universal weight
ASTM C29/C29M covers aggregate bulk density in loose and compacted conditions. That distinction matters because identical geometric volumes can contain different material mass. Ask for supplier or test data that matches the condition you are ordering.
As an explicit planning example, USACE HEC-HMS documents 93 lb/ft³ (about 1,490 kg/m³) as a default dry value for sand through gravel and says it should be replaced when another value better matches the watershed. BuildMeasure exposes the value instead of treating it as a universal gravel density.
Sources: ASTM C29/C29M-23 and USACE HEC-HMS sediment properties.
Worked example
A 12 ft × 50 ft driveway area, 4 inches deep
Use 10% allowance, 93 lb/ft³ example density, and 50 lb bags. The 4 in depth is an arithmetic example, not a universal driveway specification.
- Net volume: 12 × 50 × (4 ÷ 12) = 200 ft³.
- Net cubic yards: 200 ÷ 27 = 7.407 yd³.
- Order volume: 200 × 1.10 = 220 ft³ = 8.148 yd³.
- Estimated mass: 220 × 93 = 20,460 lb.
- Short tons: 20,460 ÷ 2,000 = 10.23 tons.
- Complete bags: round up (20,460 ÷ 50) = 410 bags.
Changing density changes the estimated tons and bags, not the measured volume. Recalculate with supplier data before purchase.
Before purchase
Verify the site and supplier assumptions
- Measure the prepared area and installed depth at multiple points.
- Confirm the aggregate type, grading, moisture, and intended use.
- Match loose or compacted density to the estimated volume state.
- Confirm delivery units, minimum loads, and whether compaction is already considered.
- Use qualified project guidance for drainage, base preparation, slopes, and structural work.
Common questions
Gravel quantity FAQ
How do I calculate cubic yards of gravel?
Multiply length by width by depth after converting depth to feet, then divide cubic feet by 27. Apply any project-specific allowance after finding the net geometric volume.
How many tons are in a cubic yard of gravel?
There is no single reliable answer because tonnage depends on the aggregate's bulk density and whether the quoted condition is loose or compacted. Multiply volume by a density supplied for the actual material and state.
Does the calculator include compaction?
No hidden compaction factor is applied. Enter a project allowance only when it matches your plan, and use a density whose loose or compacted condition matches the volume being estimated.
Should I order gravel by volume or weight?
Calculate the geometric volume first, then convert it to estimated weight only when the supplier sells by mass. Confirm the supplier's delivery increment and density basis before ordering.
Open the BuildMeasure Gravel Calculator and replace the example density with supplier data.