Divide cubic feet by 27 to get cubic yards, then multiply by density: 40 cubic feet of crushed stone is 1.48 yd³ × 1.5 = about 2.2 tons. One cubic foot of crushed stone weighs roughly 111 lb, so a ton is about 18 cubic feet.
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Cubic Feet to Tons — How the Conversion Works
The cubic foot is the small-project unit. Cubic yards make sense when a dump truck is involved, but when you’re filling a window-well drain, topping up a planter border, or patching a washed-out corner of the driveway, the numbers you measure are in feet and the total is often less than a single yard. The conversion runs in two steps: divide cubic feet by 27 (there are 27 ft³ in a cubic yard) to get cubic yards, then multiply by the material’s density in tons per yard.
You can also skip the yard entirely and think per cubic foot. Crushed stone weighs about 111 lb per cubic foot — that’s 0.056 tons — so every 18 cubic feet is a ton. This calculator does the arithmetic in both directions: enter a volume in ft³ and it returns tons, pounds, and the yard equivalent for your chosen material.
How Many Cubic Feet Are in a Ton?
| Material | lb per ft³ | ft³ per ton | 10 ft³ = |
|---|---|---|---|
| Crushed stone | 111 | 18.0 | 0.56 tons |
| #57 stone | 107 | 18.6 | 0.54 tons |
| Crusher run | 115 | 17.4 | 0.57 tons |
| Gravel | 104 | 19.3 | 0.52 tons |
| Pea gravel | 100 | 20.0 | 0.50 tons |
| River rock | 111 | 18.0 | 0.56 tons |
| Sand | 111 | 18.0 | 0.56 tons |
| Limestone | 115 | 17.4 | 0.57 tons |
| Topsoil | 81 | 24.5 | 0.41 tons |
| Lava rock | 48 | 41.5 | 0.24 tons |
Notice how tightly the dense aggregates cluster: everything from pea gravel to limestone lands between 17 and 20 cubic feet per ton. The outliers are the light materials — a ton of lava rock fills more than twice the space of a ton of crushed stone, which is exactly why it’s popular for rooftop and mulch-replacement beds.
Getting Small-Project Estimates Right
- Convert the depth first. The classic error is multiplying 6 ft × 2 ft × 4 inches and calling it 48 cubic feet. Depth must be in feet: 4 inches is 0.333 ft, and the true volume is 4 ft³ — a twelvefold difference.
- Map cubic feet onto bags. Retail bags hold 0.5 ft³, so your cubic footage × 2 is a bag count. A 9 ft³ trench backfill is 18 bags — one heaped shopping cart, no delivery fee.
- Know the bulk threshold. Once a project passes roughly 13–14 ft³ (about half a ton of stone), price a bulk pickup from the local yard before buying bags. Most quarries sell half-ton scoops loaded straight into a truck or trailer.
- Round up in the ft³ world. At this scale the waste margin is one extra bag or one extra shovel of a scoop — cheap insurance against a low spot you didn’t measure.
If your project has grown past the point where cubic feet feel natural, run the same numbers through the cubic yards to tons calculator — or start from your tape measure with the stone measurement calculator, which handles the unit conversions for you.
Frequently Asked Questions
How many cubic feet are in a ton of stone?
About 18 cubic feet for crushed stone (111 lb/ft³), 19 for gravel, and 20 for pea gravel. Lightweight lava rock stretches all the way to 41 cubic feet per ton, which is why the material selection matters.
How much does 1 cubic foot of gravel weigh?
Roughly 104 lb for common gravel, 100 lb for pea gravel, and 111 lb for crushed stone or river rock. That is about double a bag of concrete mix, so a single cubic foot is already a two-hand lift.
When should I estimate in cubic feet instead of cubic yards?
For small projects — a planter border, a short drainage trench, a repair patch — where the total is under a yard or two. Cubic feet map directly onto bagged material, since retail bags hold 0.5 cubic feet each.
How many 50-lb bags make one cubic foot?
A 50-lb bag of crushed stone holds about 0.45 cubic feet, so figure slightly more than two bags per cubic foot. Two standard 0.5 ft³ bags equal exactly one cubic foot regardless of weight.