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Calculators / Materials

How many countertop slabs do you need?

Put in each straight run of counter and pick a slab size. You'll get the square feet, a ballpark slab count, and where you'll need a seam.

These are example numbers. Put in yours.

Your counter runs

How many runs?

A run is one straight piece. An L counter is 2 runs.

in

Wall to wall, or to the open end.

in

25.5 in is standard. Islands run 36 to 42 in.

in
in
in
in

The slab

Slab size
Stone backsplash

Order this many slabs

2 slabs

58.3 sq ft of counter. Every run fits on one piece of a 120 × 55 in slab, so no seams.

Counter
58.3 sq ft
Slabs
2120 × 55 in
Seams
0
Slab used
64%

run 1 = 108 in × 25.5 in ÷ 144 = 19.1 sq ft

run 2 = 96 in × 25.5 in ÷ 144 = 17 sq ft

run 3 = 84 in × 38 in ÷ 144 = 22.2 sq ft

total = 58.3 sq ft

slab = 120 in × 55 in = 45.8 sq ft

by area = 58.3 ÷ 45.8 = 1.3, so at least 2

laid out in rows across the slab = 2 slabs, 64% used

Layout

This is a ballpark count. The fabricator lays out the real cuts around veining, chips and edge trim, and that can add a slab.

Cutouts

Don't subtract the sink or cooktop hole. You still buy that stone, and most shops charge a cutout fee on top.

Overhang

A seating overhang past about 10 in on 3 cm quartz usually needs steel supports. Check your maker's limit before you order.

See countertop support brackets on Amazon

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How we work it out

Each run is a rectangle. We add up the square feet, then lay the pieces on slabs in rows to count how many you need.

sq ft = length in × depth in ÷ 144

slabs = at least total sq ft ÷ slab sq ft, rounded up

A standard quartz slab is about 120 × 55 in. Jumbo is about 130 × 65 in. Granite varies, and 114 × 70 in is common. Any run longer than the slab needs a seam. So does an island deeper than the slab is wide.

This count is a starting point. The fabricator does the real layout around veining and flaws, and that can add a slab. Don't take out the sink hole. You still pay for that stone.

Where the numbers come from

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