Stone Slab Weight Calculator
Estimate what a granite, marble, quartzite, or quartz slab weighs — per slab and in total — from its area, thickness, and stone type.
Estimated slab weight
Weight is area × thickness × stone density. Real slabs vary a few percent by quarry and finish. Cabinets and floors must carry this load — get help and proper equipment before lifting or transporting stone.
Why weight is a planning number, not an afterthought
Stone is heavy in a way that surprises people the first time they lift a slab. A physics estimate — area times thickness times density — gives you a realistic figure well before delivery, so you can plan the handling: how many people, what lifting gear, and whether the cabinets and subfloor underneath are up to the load.
Density is what separates the stones. Granite and quartzite sit near 2.65–2.70 g/cm³, marble a touch lower, and engineered quartz lower again. Multiply by thickness and it's clear why 3 cm stone weighs so much more than 2 cm — and why moving it safely is a job for the right tools and enough hands, never brute force.
Frequently Asked Questions
How much does a stone slab weigh?
Weight is volume times density. This tool converts your area to square centimetres, multiplies by thickness to get volume, then by the stone's density. As a rule of thumb, 3 cm granite works out to roughly 16–18 pounds per square foot and 2 cm around 11–12, with marble slightly lighter and engineered quartz lighter still.
What densities does this use?
It uses common averages in grams per cubic centimetre: granite 2.70, marble 2.60, quartzite 2.65, and engineered quartz 2.40. Real stone varies by a few percent between quarries and colours, so treat the result as a close estimate rather than an exact figure.
Why does slab weight matter?
It determines whether your cabinets and floor can carry the load, how many people and what equipment are needed to move the stone safely, and whether a vehicle can transport it. A single 3 cm granite countertop can weigh several hundred pounds, so knowing the number before delivery day is a safety issue, not just a curiosity.
Is 2 cm or 3 cm stone better?
3 cm (about 1¼ inch) is the common thickness for countertops in much of North America and can often span cabinets without extra plywood support. 2 cm is lighter and cheaper but usually needs a plywood substrate or a built-up edge to look substantial. The right choice depends on your cabinets, your look, and your fabricator's recommendation.
Does the finished countertop weigh the same as the slab?
Roughly, minus the material cut away for sink and cooktop openings and the offcuts. The per-square-foot figure is the useful one for checking cabinet loading. Add the weight of any built-up (laminated) edge, which effectively doubles the thickness along the front.
Educational estimate — actual density varies by quarry and finish. Verify a slab's true weight and follow safe-handling practice before lifting or loading.