Stone calculator
Stone Weight Calculator
Enter the dimensions and stone type to get weight in pounds, kilograms and tons — plus whether it is a two-person lift or a machine job.
Your project
Weight per piece
165
lb
- Volume per piece
- 1 cu ft
- Kilograms each
- 74.8 kg
- Total for 1 piece
- 165 lb
- Total in tons
- 0.083
- Density used
- 165 lb per cu ft
- Handling
- Use a hand truck, straps and a helper — or a skid steer.
Boulder weights assume an irregular near-sphere at 85% of a true sphere's volume. Field stone varies ±15%, so treat any lifting plan as approximate and rig conservatively.
The shareable link reopens this calculator with your exact inputs.
How stone weight is calculated
Weight is volume times density. Convert every dimension to feet, multiply them for cubic feet, then multiply by the density of the rock. Granite is 165 lb/ft³, marble 170, limestone 160, sandstone 150 and slate 175.
A 3 ft × 2 ft × 2 inch granite slab is 1 cubic foot exactly, so it weighs 165 lb. Doubling the thickness to 4 inches doubles the weight — thickness is the variable people underestimate most.
Boulders are heavier than they look
A boulder's weight scales with the cube of its diameter. A 2 ft boulder is roughly 320 lb; a 3 ft boulder of the same rock is about 1,100 lb; a 4 ft boulder is over 2,600 lb. Doubling the size multiplies the weight eightfold.
That is why landscape boulders are priced and delivered by the ton, and why anything above about 400 lb is placed with a machine rather than muscle.
Stone density reference
| Stone | lb / cu ft | lb per 2" slab sq ft | kg / m³ |
|---|---|---|---|
| Granite | 165 | 27.5 | 2,643 |
| Marble | 170 | 28.3 | 2,723 |
| Limestone | 160 | 26.7 | 2,563 |
| Sandstone | 150 | 25 | 2,403 |
| Slate | 175 | 29.2 | 2,803 |
| Bluestone | 165 | 27.5 | 2,643 |
| Quartzite | 168 | 28 | 2,691 |
| Travertine | 145 | 24.2 | 2,323 |
Typical boulder weights (granite)
| Diameter | Approx. weight | Handling |
|---|---|---|
| 12" | 40 lb | One person |
| 18" | 135 lb | Two people |
| 24" | 320 lb | Machine or dolly |
| 36" | 1,080 lb | Machine |
| 48" | 2,570 lb | Machine |
Frequently asked questions
+How much does a cubic foot of stone weigh?
150-175 lb for common solid stone. Granite is 165, limestone 160, marble 170, slate 175 and sandstone about 150.
+How much does a 2 inch thick stone slab weigh per square foot?
About 27.5 lb per square foot for granite, 28 for marble and 25 for sandstone. A 1 inch slab is half that.
+How much does a 3 ft boulder weigh?
Roughly half a ton — about 1,080 lb of granite. Boulder weight grows with the cube of diameter, so estimates from photos are almost always low.
+Is stone heavier than concrete?
Yes, slightly. Normal-weight concrete is about 145 lb/ft³ while most solid stone is 150-175 lb/ft³.