Stone calculator
Flagstone Weight Calculator
Flagstone is sold by the ton with coverage that depends entirely on thickness. Enter your patio area and stone thickness.
Your project
Patios use 1-1.5" over a base. Steppers set in soil are 2".
Crews typically order 5-10% extra to cover compaction, spillage and uneven subgrade.
Flagstone needed
5.2
US tons
- Area (incl. waste)
- 504 sq ft
- Weight per square foot
- 20.6 lb
- Coverage per ton
- 97 sq ft
- Pallets (1.5 tons each)
- 4
- Estimated stone cost
- $1,819
Order 10-15% extra. Irregular flagstone needs trimming to fit, and the pieces you cut down do not always come back as usable fill.
The shareable link reopens this calculator with your exact inputs.
Coverage per ton is a thickness question
Thin 3/4 inch flagstone covers around 180-200 sq ft per ton. Standard 1-1.5 inch patio stone covers 100-140. Thick 2 inch steppers cover only 70-90. Every quote you get should state the thickness range, because "one ton of flagstone" means nothing without it.
Sandstone at 150 lb/ft³ covers more area per ton than bluestone at 165, which is one reason regional stone choices differ so much in delivered cost per square foot.
Dry-laid or mortared
Dry-laid flagstone sits on 1 inch of screed bedding over 4 inches of compacted base, with joints filled with polymeric sand or stone dust. Mortared flagstone needs a concrete slab underneath — laying mortar over compacted stone alone guarantees cracking within a couple of freeze cycles.
For a dry-laid patio, 1.5 inch minimum thickness is the practical floor. Thinner stone cracks when a chair leg concentrates load over a small void in the bedding.
Flagstone coverage per ton (sandstone, 150 lb/ft³)
| Thickness | lb / sq ft | Sq ft per ton |
|---|---|---|
| 0.75" | 9.4 | 213 |
| 1" | 12.5 | 160 |
| 1.25" | 15.6 | 128 |
| 1.5" | 18.8 | 107 |
| 2" | 25 | 80 |
| 2.5" | 31.3 | 64 |
Frequently asked questions
+How much does flagstone weigh per square foot?
About 12.5 lb per square foot at 1 inch thick for sandstone, 18.75 lb at 1.5 inches and 25 lb at 2 inches. Denser bluestone is roughly 10% heavier.
+How many square feet does a ton of flagstone cover?
100-140 sq ft for standard 1-1.5 inch patio stone, up to 200 sq ft for thin 3/4 inch stone, and as little as 70 sq ft for 2 inch steppers.
+How much does a pallet of flagstone weigh?
Typically 1.5-2 tons — 3,000 to 4,000 lb — which covers roughly 150-250 square feet depending on thickness.
+How thick should flagstone be for a patio?
1.5 inches minimum for dry-laid work over compacted base. Thinner stone can be used only when it is mortared to a concrete slab.