Gravel & Base Calculator
Gravel is quoted by the ton but measured by volume. Enter the area and depth to get both — plus a compaction allowance, because crusher run settles and the loose volume you order is not the compacted depth you end up with.
How to use this calculator
- Measure the area to be covered, not the excavation. For an irregular driveway, split it into rectangles and run the tool twice.
- Set the depth by job, not by feel. The reference table below gives the usual figures. A driveway is normally two layers — a coarse base and a finer top — so calculate each layer separately.
- Pick the material, because tonnage per cubic yard varies. Crusher run is the heaviest of the common choices and pea gravel among the lightest.
- Keep the compaction allowance for anything that gets tamped. Crusher run loses roughly 15–20% of its loose volume when compacted, so ordering the finished depth leaves you short.
The formula
Volume first, then weight — because gravel is measured by volume and sold by the ton:
cubic feet = area (sq ft) × depth (in) ÷ 12
cubic yards = cubic feet ÷ 27
tons = cubic yards × tons per cubic yard
| Material | Tons per cu yd | lb per cu yd |
|---|---|---|
| Crusher run / quarry process | 1.50 | 3,000 |
| Crushed stone #57 (3/4 in) | 1.40 | 2,800 |
| Decomposed granite | 1.40 | 2,800 |
| Pea gravel | 1.35 | 2,700 |
| River rock | 1.35 | 2,700 |
| Bedding sand | 1.30 | 2,600 |
These are typical dry figures. Wet material weighs more per yard, and quarries differ — the number on your quote wins.
Worked example
A 40 × 10 ft driveway topped with 4 in of #57 crushed stone, 15% compaction allowance:
- Area: 40 × 10 = 400 sq ft
- Depth in feet: 4 ÷ 12 = 0.333 ft
- Volume: 400 × 0.333 = 133 cu ft
- With 15%: 153 cu ft = 153 ÷ 27 = 5.68 cu yd
- Tons: 5.68 × 1.40 = 7.95 tons
Eight tons is 15,900 lb — three or four pickup loads if the truck could even take a ton at a time, which most cannot. This is the volume at which a delivery is not a convenience but the only sensible option.
Depth by job
| Job | Depth | Notes |
|---|---|---|
| Garden path, walkway | 2–3 in | Over landscape fabric |
| Paver or flagstone base | 4 in gravel + 1 in sand | Compact the gravel in 2 in lifts |
| Driveway base layer | 4–6 in | Crusher run, compacted |
| Driveway top layer | 3–4 in | #57 or decorative stone |
| Shed or slab sub-base | 4 in | Compacted crushed stone |
| French drain backfill | Trench volume | Washed stone, no fines |
| Fire pit or grill pad | 3–4 in | Lava rock or gravel |
Frequently asked questions
How many tons of gravel do I need?
Work out the volume first: area in square feet times depth in inches divided by 12 gives cubic feet, and dividing by 27 gives cubic yards. Multiply cubic yards by about 1.4 for crushed stone or 1.5 for crusher run to get tons.
How much does a yard of gravel weigh?
Roughly 2,700 to 3,000 pounds dry, depending on the stone. Crusher run is the heaviest at about 3,000 pounds per cubic yard, crushed stone around 2,800, and pea gravel closer to 2,700. Wet material weighs more.
How deep should gravel be for a driveway?
Typically a compacted base of 4 to 6 inches of crusher run with a 3 to 4 inch top layer of #57 or decorative stone. Calculate the two layers separately, since they use different material and different depths.
Do I need to add extra for compaction?
Yes for anything that gets tamped. Crusher run and other material with fines loses roughly 15 to 20 percent of its loose volume when compacted, so order the loose volume and you finish at the depth you wanted. Loose decorative stone that is never compacted needs no allowance.
How much area does a ton of gravel cover?
About 100 square feet at 2 inches deep, 70 square feet at 3 inches, and 50 square feet at 4 inches for typical crushed stone. Coverage falls as depth rises, in direct proportion.