Calculate your materials
What you'll need to buy
- Flagstone (by the ton)Sandstone, bluestone, or quartzite slabsShop
- Polymeric sandLocks joints between stones and resists weedsShop
- Paver base / crushed stone4" compacted base under the setting bedShop
- Bedding sand1" leveling layer beneath each stoneShop
- Landscape fabricOptional weed barrier under the baseShop
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How the math works
A 12 ft × 12 ft patio = 144 sq ft. Using 1.5" sandstone, coverage is 110 × (1 ÷ 1.5) ≈ 73 sq ft/ton. With 10% waste: 144 × 1.10 ÷ 73 ≈ 2.2 → order 3 tons.
Formula
Reference values
| Thickness | Coverage per ton |
|---|---|
| 1" | ≈ 110–120 sq ft / ton |
| 1.5" | ≈ 75–80 sq ft / ton |
| 2" | ≈ 60–80 sq ft / ton |
| 2.5" | ≈ 45–55 sq ft / ton |
Step by step
- Measure the patio length and width, then multiply for square footage.
- Choose your stone thickness (1.5" is typical for patios).
- Look up coverage per ton for that thickness.
- Add 10–20% waste, then divide square footage by coverage to get tons. Round up.
Waste allowance
Always add a waste factor: more for diagonal, herringbone, or irregular layouts and for trenches in rocky soil. It's cheaper to round up than to pay for a second delivery.
Bags vs. bulk
Bagged material is convenient for small jobs, but loose/bulk delivery is almost always cheaper per unit once you pass roughly 1–3 cubic yards. Compare the per-cubic-yard price before deciding.
Frequently asked questions
How many square feet does a ton of flagstone cover?
It depends on thickness. A ton of 1" flagstone covers roughly 110–120 sq ft, 1.5" covers about 75–80 sq ft, and 2" covers around 60–80 sq ft. Thicker stone weighs more, so it covers less area per ton.
How much flagstone do I need for a 200 sq ft patio?
For a 200 sq ft patio in 1.5" flagstone (≈73 sq ft/ton) with 10% waste, you'd need about 200 × 1.10 ÷ 73 ≈ 3 tons. Always round up to the next full ton.
Should I add waste when ordering flagstone?
Yes. Add 10% for cut/straight layouts, 15% for irregular random patterns, and up to 20% when there are many cuts. Flagstone breaks during fitting, so the extra prevents a second delivery.
Is flagstone sold by the ton or square foot?
Most stone yards sell flagstone by the ton, though some price it per square foot of pallet. This calculator returns tons because that's how bulk flagstone is usually quoted and delivered.
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