Flagstone Calculator

Determine exact flagstone tonnage, pallet counts, and joint mortar coverage for natural stone patios and garden walkways.

Patio or Walkway Area (Square Feet)

Stone Thickness

Joint Gap Width

Natural Flagstone to Order

4.5 Tons

~3 Pallets (at 1.5 tons per pallet)

Crushed Base Stone 6.1 Tons 4" compacted base

Stone Dust Joint Fill 0.8 Tons Decomposed granite / dust

Thickness Rule of Thumb Use 1.5" to 2" flagstone for sand or gravel dry-laid installations. Thin 1" stone will crack under foot traffic unless mortared onto a poured 4-inch concrete slab.

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How Flagstone Coverage and Tonnage Work

Quarried flagstone (sandstone, limestone, slate, quartzite) is sold by weight in short tons (2,000 lbs). The thinner the stone, the more surface area one ton will cover:

1 Inch Thick: Covers 120 to 140 square feet per ton (wet-lay over concrete only).
1.5 Inches Thick: Covers 85 to 95 square feet per ton (standard dry-lay over sand/gravel).
2 Inches Thick: Covers 65 to 75 square feet per ton (heavy stepping stones).

Frequently Asked Questions

How much does a pallet of flagstone weigh?

A standard wire-caged pallet of flagstone weighs between 3,000 and 4,000 lbs (1.5 to 2.0 tons).

What is the best base for dry-laying flagstone?

Install 4 inches of compacted #21A crusher run stone base, topped with 1 inch of coarse concrete sand or stone dust to level the uneven thicknesses of natural stone.

How much waste should I add for irregular flagstone?

Plan on 10% to 15% waste for normal irregular flagstone puzzle fit-up, or 20% to 25% if hand-chiseling edges for tight formal joints.