Estimate gravel or rock in cubic yards and tons, with weight that matches supplier scale tickets.
Quick answer: Multiply length × width × depth in feet and divide by 27. A 20 × 20 ft driveway at 4 inches deep needs (20 × 20 × 0.333) / 27 = 4.94 cubic yards of gravel — about 6.9 tons. Add 10 to 15 percent extra for compaction.
Ballpark, not gospel. Density varies by rock type and moisture — confirm tons-per-yard with your supplier before ordering, especially for hauling limits.
| Driveway size | 4 in deep | 6 in deep | Tons at 4 in |
|---|---|---|---|
| 10 x 20 (single car) | 2.47 yd | 3.70 yd | 3.5 |
| 12 x 40 | 5.93 yd | 8.89 yd | 8.3 |
| 20 x 20 (two car) | 4.94 yd | 7.41 yd | 6.9 |
| 20 x 50 | 12.35 yd | 18.52 yd | 17.3 |
Ton figures use 2,800 lbs per yard for standard gravel. Build driveways in layers — count the full base depth, not just the top layer.
Straight answers, no fluff. Then run your own numbers above.
Measure length and width in feet, multiply by gravel depth in feet, then divide by 27. A 3 inch depth is 0.25 feet.
Using 2,800 lbs per cubic yard, gravel is about 1.40 tons per cubic yard. River rock and crushed stone can vary.
A 20x20 ft driveway at 4 inches needs about 4.94 cubic yards, or roughly 6.9 tons of standard gravel. At 6 inches deep it needs about 7.41 yards (10.4 tons). Add 15 percent for compaction.
A compacted base of larger crushed stone (such as crusher run) topped with 2 to 3 inches of 3/4 inch crushed stone (#57) is the standard durable combination.
Many suppliers sell gravel by the ton. Use cubic yards for volume planning and tons for ordering when needed.
Order about 10 percent extra for compaction, uneven base, and spreading loss. Larger jobs may need a supplier review.
Quoted by weight? The tons-to-yards converter goes both directions, and the sand calculator handles paver bedding.