Stone Slab Weight Calculator

Multiply the slab area by its thickness to get volume, then multiply by the density of the stone. For granite, density is about 2,700 kg/m³ (168 lb/ft³). So a 3.05 m by 1.65 m slab of 3 cm granite equals 3.05 × 1.65 × 0.03 × 2700, which is about 408 kg (900 lb).

About 16 to 17 lb per square foot, so a full slab of roughly 120 by 65 inches weighs around 900 lb (408 kg). A 2 cm slab of the same size weighs about a third less, near 600 lb (272 kg).

Marble is a little lighter than granite at about 2,560 kg/m³ (160 lb/ft³). A 2 cm marble slab weighs roughly 10 to 11 lb per square foot, and a full slab can still run 500 lb or more, which is why fabricators handle it with a vacuum lifter rather than by hand.

Granite and quartzite are close, both around 2,650 to 2,700 kg/m³. Marble is a bit lighter at about 2,560 kg/m³, and engineered quartz is lighter again near 2,400 kg/m³. For the same size and thickness, granite and quartzite are the heaviest of the common countertop stones.

Engineered quartz runs about 2,400 kg/m³ (150 lb/ft³), a little lighter than granite. A standard 3 cm quartz slab weighs around 14 to 15 lb per square foot, so a full jumbo slab is commonly 700 to 800 lb.

Once a slab is over about 150 to 200 lb, hand carrying is slow and is the main cause of back and crushed-finger injuries in stone shops, along with chipped edges. A vacuum lifter grips the slab face so one operator can move and place slabs up to 1,800 lb (820 kg) safely.