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Stone Weight Calculator

Construction

Calculate the weight of a rectangular stone slab from length, width, thickness, and stone type. Get per-piece and total weight for granite, marble, and more.

1120
1120
0.2512
1

Total Weight

113.33
Weight per Piece
113.33

This calculator computes your Total Weight, Weight per Piece from the values you enter.

Inputs
LengthWidthThicknessStone TypeQuantity
Outputs
Total WeightWeight per Piece

What is a Stone Weight?

A Stone Weight Calculator estimates how much a rectangular piece of natural stone weighs based on its length, width, thickness, and material type. Natural stone — granite, marble, limestone, sandstone, and basalt — varies significantly in density, so a slab of granite and a same-sized slab of sandstone can differ in weight by 15% or more. This tool converts your slab dimensions into cubic feet and multiplies by the correct density for your stone type to give you an accurate weight figure.

This calculation matters most for countertop fabricators, masons, and general contractors who need to know slab weight before transport, lifting, or installation. A single kitchen island slab can weigh several hundred pounds, and getting that number wrong can mean an undersized crew, an overloaded cabinet base, or a shipping quote that's off by a wide margin. If you're also estimating other stone or aggregate materials for a project, the Limestone Calculator and Cubic Yard Calculator cover bulk stone and fill volumes.

Unlike generic weight estimators, this calculator is built specifically around slab geometry — length × width × thickness — and a curated set of common natural stone densities, so you don't need to look up density tables or do unit conversions by hand.

How to use this Stone Weight calculator

  1. Enter the slab Length in inches using the input field or slider.
  2. Enter the slab Width in inches.
  3. Enter the slab Thickness in inches — standard countertop slabs are commonly 0.79 in (2cm) or 1.18 in (3cm).
  4. Select the Stone Type from the dropdown — Granite, Limestone, Sandstone, Marble, or Basalt.
  5. Set the Quantity if you're calculating for more than one identical piece.
  6. Review the Total Weight and Weight per Piece results to plan your lift, shipping, or structural support needs.

Formula & Methodology

The calculator converts slab dimensions to volume, then applies material density:

Volume (ft³) = (Length × Width × Thickness) ÷ 1,728

Weight per Piece (lb) = Volume (ft³) × Density (lb/ft³)

Total Weight (lb) = Weight per Piece × Quantity

Density values used: Granite = 170 lb/ft³, Limestone = 165 lb/ft³, Sandstone = 145 lb/ft³, Marble = 175 lb/ft³, Basalt = 180 lb/ft³.

Worked example: A granite countertop slab measuring 96 in × 26 in × 1.18 in (3cm thick):

Volume = (96 × 26 × 1.18) ÷ 1,728 = 1.70 ft³

Weight per piece = 1.70 × 170 = 289 lb

For a quantity of 2 identical slabs, Total Weight = 289 × 2 = 578 lb.

Frequently Asked Questions

Multiply the slab's length, width, and thickness (all in inches) to get the volume in cubic inches, then divide by 1,728 to convert to cubic feet. Multiply that volume by the stone's density in pounds per cubic foot to get the weight of a single piece. Multiply by the quantity if you're ordering more than one slab.
Weight equals volume times density: Volume (ft³) = (Length × Width × Thickness) ÷ 1,728, and Weight (lb) = Volume × Density. Densities vary by stone type — granite runs about 170 lb/ft³, while marble is closer to 175 lb/ft³.
Density differences come down to mineral composition and porosity. Granite is a dense igneous rock made of tightly interlocked quartz and feldspar crystals, while sandstone is a sedimentary rock with more air pockets between grains, making it noticeably lighter per cubic foot.
Granite typically weighs around 170 lb/ft³ and marble around 175 lb/ft³, so marble is slightly heavier for the same dimensions. The difference is small enough that it rarely changes a structural decision, but it matters when you're close to a weight limit for cabinetry, flooring joists, or shipping.
A 3cm-thick slab is roughly 1.18 inches thick. For a typical 96-inch by 26-inch countertop section, that works out to about (96 × 26 × 1.18) ÷ 1,728 = 1.7 ft³, which at 170 lb/ft³ comes to roughly 289 pounds. Use the calculator above with your exact dimensions for a precise figure.
Enter the slab's length, width, and thickness in inches, select the stone type from the dropdown, and set the quantity if you need more than one piece. The calculator instantly returns the total weight and the weight per individual piece.
This calculator assumes a rectangular slab, which covers most countertops, pavers, and tile. For irregular shapes, estimate the bounding rectangle dimensions for a conservative upper-bound weight, or break the shape into rectangular sections and sum the results.
Countertop installers, cabinet makers, and flooring contractors need slab weight to plan lifting equipment, verify that cabinets or subfloors can bear the load, and calculate freight costs. Underestimating weight can lead to structural failure or an installation crew that's under-equipped for the job.
Common natural stone densities range from about 140 lb/ft³ for lighter sandstones to 185 lb/ft³ for dense basalt. If your specific stone isn't listed, choose the closest match by rock type — granite for igneous stones, limestone or sandstone for sedimentary stones, and marble for metamorphic stones.
Yes — thickness scales weight linearly, so doubling the thickness doubles the weight. Moving from a 2cm to a 3cm slab (roughly 0.79 in to 1.18 in) increases weight by about 50%, which is why thicker slabs often need additional support brackets or reinforced cabinetry.
The calculator uses standard published density values for each stone type, which are accurate to within a few percent for most quarried stone. Natural variation in mineral content and moisture can shift actual weight slightly, so for critical structural calculations, confirm density with your supplier's spec sheet.
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