Material calculator
Drainage Stone calculator
Enter your area and depth to get drainage stone in tons, cubic yards, bulk bags and delivered cost. Drainage Stone is placed at about 100 lb per cubic foot, or 1.35 tons per cubic yard.
Your project
Drainage Stone for French drains, wall backfill and dry wells is typically placed 12" deep.
Crews typically order 5-10% extra to cover compaction, spillage and uneven subgrade.
Drainage Stone required
25.2
US tons (incl. 5% waste)
- Area
- 480 sq ft
- Volume
- 18.67 cu yd
- Volume (cubic feet)
- 504
- Tons per cubic yard
- 1.35
- Bulk bags (1 ton each)
- 26
- Dump truck loads
- 2
- Delivered material cost
- $1,336
#57 clean stone has roughly 40% void space, so it moves water fast and stays free-draining when wrapped in geotextile.
How much drainage stone do you need?
Volume first, weight second. Multiply area in square feet by depth in feet, divide by 27 for cubic yards, then multiply by 1.35 to convert to tons — that is the placed density of drainage stone at roughly 100 lb per cubic foot.
For French drains, wall backfill and dry wells, 12 inches is the standard depth. Going shallower to save on material is a false economy: thin layers rut, migrate and expose the subgrade within a season.
#57 clean stone has roughly 40% void space, so it moves water fast and stays free-draining when wrapped in geotextile.
Ordering and delivery
Yards sell drainage stone by the ton but stockpile it by the yard, so quote both numbers when you call. A standard tandem dump truck carries about 15 tons; anything under a ton usually comes in bulk bags at a significant premium per ton.
Delivered pricing runs $30 – $75 per ton depending on haul distance from the quarry. Freight, not the stone itself, is usually the larger half of that number.
Drainage Stone coverage per ton
At 100 lb per cubic foot placed.
| Depth | Coverage per ton | Tons per 100 sq ft | Cu yd per 100 sq ft |
|---|---|---|---|
| 1" | 240 sq ft | 0.42 | 0.31 |
| 2" | 120 sq ft | 0.83 | 0.62 |
| 3" | 80 sq ft | 1.25 | 0.93 |
| 4" | 60 sq ft | 1.67 | 1.23 |
| 6" | 40 sq ft | 2.5 | 1.85 |
| 12" | 20 sq ft | 5 | 3.7 |
Frequently asked questions
+How many tons of drainage stone are in a cubic yard?
About 1.35 tons. Drainage Stone weighs roughly 100 lb per cubic foot placed, and a cubic yard is 27 cubic feet, so 27 × 100 ÷ 2,000 = 1.35 tons.
+How much area does a ton of drainage stone cover?
At 12 inches deep, one ton covers about 20 square feet. At 2 inches it covers roughly 120 square feet.
+How deep should drainage stone be laid?
12 inches is standard for French drains, wall backfill and dry wells. Over soft or clay subgrade, add 2 inches and place a woven geotextile separator so the stone does not disappear into the soil.
+Should I order extra?
Yes — 5 to 10%. Spread depth is never perfectly uniform, the subgrade has low spots, and coming up half a ton short means paying a second delivery fee that often exceeds the value of the material.
+What does drainage stone cost?
Delivered, $30 – $75 per ton in most US markets, versus $25 – $80 per ton across aggregates generally. Picking it up yourself saves the haul but rarely more than a few dollars a ton once fuel is counted.
+Do I need landscape fabric underneath?
Under decorative stone, yes — it slows weed growth and keeps the stone out of the soil. Under a compacted structural base, use a woven geotextile separator rather than a light weed fabric, which will tear during compaction.