Marble & Granite Calculator
Use this marble calculator for a floor by area, or list the pieces you need cut, such as a counter, stair treads or sills, and it fits them onto slabs. You get the area or slab count with the yield, the weight for handling at your thickness and density, and the cost at your price.
Marble & granite calculator
Weights are estimates for handling and transport, not a structural check. Stone slabs are heavy; ask your fabricator about lifting, support and overhangs. Quantities are estimates. Buy from one batch and keep a few spare pieces for repairs.
Bare numbers are mm.
Your price, any currency. Leave blank to skip.
Assumptions
Change any value to match your product or local rules.
Basis: Example allowance for cuts and breakage. Your installer’s figure wins; the Tile Layout Planner counts the cuts for one room.
Basis: Example. Stone density varies; ask your supplier.
- Stone area
- 16.63 m²
- 179.0 sq ft
- Slabs
- Floor bought by area
- Yield (pieces ÷ slabs bought)
- Floor bought by area
- Weight of the stone
- 808.3 kg
- 1,782.0 lb
- One slab weighs
- Floor bought by area
- Cost (your currency)
- Add a price to see the cost
Buy 16.63 m² of 18 mm stone for 15.12 m² of floor; it weighs about 808.3 kg.
How this was calculated
- Floor: area to buy = floor area × (1 + wastage); weight = area × thickness × density
- Pieces: placed on slabs in shelves along the slab length, a kerf between pieces, inside the edge margin; yield = piece area ÷ (slabs × slab area)
- Weight of pieces = piece area × thickness × density; one slab = slab area × thickness × density
- Area = 4.20 m × 3.60 m = 15.12 m²
- Area to buy = 15.12 m² × (1 + 10.0%) = 16.63 m²
- Weight = 16.63 m² × 18 mm × 2,700 kg/m³ = 808.3 kg
How it works
Pick floor or pieces
A floor bought by area, or pieces such as a counter, treads or sills cut from slabs.
Enter the sizes
Rooms or a total area for a floor. For pieces, each piece’s length, width and count, and the slab size your supplier stocks.
Set thickness and density
The thickness of your stone and its density. The 2,700 kg/m³ default is an example; ask your supplier.
Read slabs, yield and weight
The slab count with the pieces on each slab, the yield, the weight of the pieces and of one slab, and the cost if you enter a price.
Worked example
A counter of 2.4 × 0.62 m and a return of 1.8 × 0.62 m from slabs of 2.8 × 1.6 m, with 20 mm of unusable edge and a 5 mm saw cut. The usable slab is 2.76 × 1.56 m. The counter takes the first row; the return does not fit beside it (2.4 + 0.005 + 1.8 = 4.205 m), so it starts a second row at 0.625 m. One slab holds both: 2.604 m² of pieces from 4.48 m² of slab is a 58.1% yield. At 20 mm and 2,700 kg/m³ the pieces weigh 140.6 kg and the whole slab 241.9 kg.
In inches: 96 × 25.5 and 72 × 25.5 from a 110 × 63 in slab with a 3/4 in edge also fit on one slab, 29.75 sq ft of pieces, a 61.8% yield. At 3/4 in thick the pieces weigh about 313 lb.
A floor: 15.12 m² of 18 mm marble with 10% added is 16.63 m², about 808 kg.
How to measure marble in square feet
Measure each piece or room at its longest length and width. In feet, the area is length × width in square feet. In inches, multiply length × width and divide by 144, the number of square inches in a square foot. The 96 × 25.5 in counter above is 2,448 sq in ÷ 144 = 17 sq ft, and the 72 × 25.5 in return is 12.75 sq ft, so the pieces total 29.75 sq ft. For a floor, add your wastage allowance to the room area; for cut pieces, the quantity to buy is the slabs they fit on, not their area alone.
Granite calculator: same maths as marble
Marble and granite are bought the same ways, by area or by slab, and weigh area × thickness × density. Only the density and the slab sizes change between stones and suppliers, and both are fields here. Use the presets for a marble floor or a granite counter, then change the figures to your stone.
Floors by area
Stone floor tiles and cut-to-size floors are sold by area. The calculator adds your wastage allowance to the floor area and gives the weight of what you buy, which matters for delivery and for carrying it upstairs.
Counters, stairs and sills from slabs
List each piece with its length, width and count. The calculator lays the pieces in rows along the slab, longest first, with a saw cut between them and inside the unusable edge, and opens a new slab when nothing else fits. Pieces may turn unless you keep the grain direction. Cut-outs for sinks and hobs are not taken off; fabricators cut them from the piece.
Yield and offcuts
Yield is the area of your pieces over the area of the slabs you buy. Below 100% means offcuts: the edge, the saw cuts and the parts no piece fits. Ask whether you keep the offcuts; they can make sills, shelves or a hearth. A fabricator who nests pieces by hand may beat the rows used here.
Weight and handling
Weight = area × thickness × density. The result is an estimate for handling and transport, not a structural check. Ask your fabricator and installer about lifting, support under the stone and how far a counter can overhang.
Frequently asked questions
How do I calculate marble for a floor?
Multiply the floor area by 1 plus your wastage allowance. A 15.12 m² floor with 10% added needs 16.63 m². For weight, multiply that area by the thickness and the stone’s density.
How do I calculate marble in square feet?
Multiply length × width in feet, or multiply length × width in inches and divide by 144. A 96 × 25.5 in piece is 2,448 ÷ 144 = 17 sq ft. Add your wastage allowance for a floor.
How many granite slabs do I need for my counter?
List the counter pieces and enter your supplier’s slab size, the edge they trim and the saw cut. The calculator fits the pieces onto slabs and gives the count. A 2.4 m counter and a 1.8 m return, both 0.62 m deep, fit on one 2.8 × 1.6 m slab.
How much does a granite slab weigh?
Slab area × thickness × density. With an example density of 2,700 kg/m³, a 2.8 × 1.6 m slab 20 mm thick weighs 241.9 kg. Ask your supplier for your stone’s density.
Why is the yield below 100%?
Slabs have an edge that is trimmed, every cut loses a saw blade’s width, and pieces rarely fill a slab. The yield shows how much of the stone you buy ends up in your pieces.
Is marble sold per square foot or per slab?
Both. Enter the price the way your supplier quotes it. Per-area prices can count the whole slab or only your pieces, so check what your quote covers.
Ready to plan your space?
It is free, runs in your browser and needs no account. Projects are saved privately on this device.