How Much Does a Ton of Flagstone Cover? Chart by Thickness

How much does a ton of flagstone cover? It depends almost entirely on how thick the stone is. A ton of 1-inch flagstone covers roughly 150 square feet, a ton of 1.5-inch stone covers about 100 square feet and a ton of 2-inch stone covers about 75 square feet. Thicker steppers cover even less. This guide shows where those numbers come from, gives a coverage chart by thickness, a weight per square foot table and a simple way to work out how many tons to order for a patio or path.

The short answer

• Rule of thumb: about 150 sq ft per ton at 1 inch thick, 100 sq ft at 1.5 inches, 75 sq ft at 2 inches and 50 sq ft at 3 inches.
• Why it changes so much: flagstone is sold by weight, and a stone twice as thick weighs twice as much for the same face area, so it covers half the ground.
• Weight per square foot: roughly 13 lb at 1 inch, 20 lb at 1.5 inches and 27 lb at 2 inches.
• Order a little extra. Irregular shapes, cuts and broken pieces mean most jobs need around 10 percent more than the bare math, and more for small, odd-shaped stone.

Related: How Much Does a Ton of Gravel Cover? Depth Chart

Flagstone coverage per ton by thickness

These figures assume stone that weighs about 160 pounds per cubic foot, a middle value for the sandstone, limestone and quartzite that most flagstone is cut from. They are the area of stone face you get from one 2,000-pound ton, before gaps between stones or cutting waste.

• 3/4 inch: about 200 sq ft per ton
• 1 inch: about 150 sq ft per ton
• 1.25 inches: about 120 sq ft per ton
• 1.5 inches: about 100 sq ft per ton
• 2 inches: about 75 sq ft per ton
• 2.5 inches: about 60 sq ft per ton
• 3 inches: about 50 sq ft per ton

Lighter, more porous sandstone gives a bit more area per ton than the chart, and dense quartzite or slate gives a bit less. At 1.5 inches, for example, the range runs from roughly 90 to 110 square feet per ton depending on the stone.

How much does flagstone weigh per square foot?

One square foot of stone 1 inch thick is 1/12 of a cubic foot. Multiply by the stone’s weight per cubic foot and you have its weight per square foot. At about 160 pounds per cubic foot:

• 1 inch thick: about 13 lb per sq ft
• 1.5 inches thick: about 20 lb per sq ft
• 2 inches thick: about 27 lb per sq ft
• 3 inches thick: about 40 lb per sq ft

That makes single stones easy to estimate. A 2 by 2 foot flag, 4 square feet, weighs about 80 pounds at 1.5 inches and about 107 pounds at 2 inches. A 3 by 3 foot stepper 2 inches thick is close to 240 pounds, which is a two-person or hand-truck lift.

Related: How Many Square Feet Does a Ton of Asphalt Cover?

The formula

1. Weight per square foot = thickness in inches ÷ 12 × weight per cubic foot (use about 160 if you do not know the stone).
2. Square feet per ton = 2,000 ÷ weight per square foot.
3. Tons needed = area to cover in square feet ÷ square feet per ton, then add about 10 percent.

Use the average thickness of the stone, not the thinnest piece. Flagstone sold as “1 to 2 inch” varies across that whole range, so 1.5 inches is a fair average for that kind of lot, and a lot labeled “1.5 to 2.5 inch” averages closer to 2 inches.

Worked examples

• 12 × 14 ft patio, dry laid, 1.5 to 2 inch stone: 168 sq ft. At an average of about 1.75 inches, each square foot weighs about 23 lb, so a ton covers about 86 sq ft. 168 ÷ 86 = 1.95 tons, plus 10 percent = about 2.15 tons. Order about 2 1/4 tons.
• 10 × 10 ft patio set in mortar on a slab, 1 inch stone: 100 sq ft ÷ 150 = 0.67 ton, plus 10 to 15 percent = about 3/4 ton.
• 3 × 30 ft stepping-stone path, 2 inch steppers: if the stones cover about 60 percent of the path with grass or gravel between them, you need about 54 sq ft of stone. 54 ÷ 75 = 0.72 ton, so plan on about 3/4 ton.
• Metric: stone 40 mm thick at about 2,560 kg per cubic meter weighs about 102 kg per square meter, so a metric tonne covers roughly 9.8 square meters.

Gaps, cuts and waste

• Joints add a little area. Gaps between stones, whether mortar, stone dust, polymeric sand or moss, are area you do not have to fill with stone. Wide dry-laid joints can stretch a ton a bit further than the chart.
• Cuts and breakage take it back. Trimming stones to fit edges, rejecting cracked pieces and the odd shapes that never quite fit all use up stone.
• Small pieces cost coverage. A pallet of small, irregular stones leaves more gaps and needs more fitting than one of large flags, so add closer to 15 percent.
• Steppers are different. For a path of spaced stones, estimate the area of the stones themselves, not the whole path.

Choosing a thickness

Thickness drives both the tonnage and how the stone holds up.

• Mortared onto a concrete slab: thinner stone, around 1/2 to 1 inch, is common because the slab carries the load. More area per ton, but you need a sound slab underneath; see concrete patio thickness.
• Dry laid on gravel and sand: thicker stone, often 1.5 to 2 inches or more, resists cracking and rocking when it is not glued to a slab.
• Stepping stones in lawn or gravel: 2 to 3 inches or thicker, so each stone stays put on its own.

Don’t forget the base

A dry-laid flagstone patio sits on a compacted gravel base with a thin setting bed on top, and that base usually weighs more than the stone. Our guide to the flagstone patio base works through depth and tons for the same 12 × 14 foot patio, and the crushed stone calculator and sand calculator handle any size. For joint fill, see polymeric sand coverage.

Buying flagstone by the ton or pallet

• Ask how it is sold. Stone yards commonly sell flagstone by the ton, by the pallet or by the square foot. If it is by the pallet, ask what the pallet weighs and the stone’s thickness range so you can use the chart.
• Ask for the yard’s own coverage figure. Suppliers who handle one stone every day often know what it really covers per ton. Compare it with the math above.
• Pick from one lot. Color and thickness can vary between lots, so buy enough at once and add a few spare stones for future repairs.
• Check your hauling limits. Two tons is more than most pickups and many small trailers are rated for, so compare the weight with your truck’s payload and trailer rating or have it delivered. Our post on how much a pallet of pavers weighs covers the same payload math.

Common mistakes

• Using the thinnest stone in the pile as the thickness, which underestimates tons.
• Mixing up square feet per ton and square feet per pallet.
• Ordering the exact math with no allowance for cuts and odd shapes.
• Buying thin stone for a dry-laid patio, where it is more likely to crack.
• Forgetting that the base gravel and setting sand are separate, heavier orders.

Questions people ask

How many square feet does a ton of flagstone cover?

About 150 square feet at 1 inch thick, 100 at 1.5 inches, 75 at 2 inches and 50 at 3 inches, for stone weighing around 160 pounds per cubic foot. Lighter sandstone covers a little more and dense quartzite or slate a little less.

How much does flagstone weigh per square foot?

Roughly 13 pounds per square foot at 1 inch thick, 20 pounds at 1.5 inches, 27 pounds at 2 inches and 40 pounds at 3 inches.

How many tons of flagstone do I need?

Divide the area in square feet by the coverage per ton for the stone's average thickness, then add about 10 percent for cuts and odd shapes. A 12 x 14 foot patio in 1.5 to 2 inch stone works out to about 2 1/4 tons.

How much does a 2x2 flagstone weigh?

A 2 by 2 foot piece covers 4 square feet, so it weighs about 80 pounds at 1.5 inches thick and about 107 pounds at 2 inches.

How much does a pallet of flagstone cover?

It depends on the pallet's weight and the stone's thickness. Ask the yard what the pallet weighs, divide by the weight per square foot for that thickness and take off about 10 percent for waste.

What thickness of flagstone is best for a patio?

Stone set in mortar on a concrete slab is often about 1/2 to 1 inch thick. For a dry-laid patio on gravel and sand, 1.5 to 2 inches or thicker holds up better, and stepping stones are usually 2 inches or more.

Related guides

• Flagstone patio base: gravel, sand and depth
• How much does a ton of river rock cover?
• How much does a ton of crushed stone cover?
• How much does a boulder weigh?
• How many pavers per square foot

Open the crushed stone calculator →

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