How many slabs of granite do I need for my kitchen?

Take the finished area you need, add the waste factor, divide by the usable area of the slab and round up. A standard quartz slab covers 45.83 square feet, a jumbo 58.68 and a super jumbo 75.7. Granite loses about 18 percent to off-cuts against quartz's 12, because it is quarried rather than manufactured and its edges are irregular. So a 55 square foot kitchen in granite is 55 times 1.18, which is 64.9 square feet, which is two jumbo slabs rather than one.

Why is the answer always a whole number?

Because nobody sells part of a slab. That sounds obvious and it is the most expensive thing on this page, because it means two kitchens a few square feet apart can be a whole slab apart in price. A job that spills two square feet over a boundary buys an entire extra slab and throws most of it away. Anything that returned 1.7 slabs would be arithmetically tidy and completely useless for planning.

What is a waste factor and why does granite have a higher one?

It is the share of a slab that ends up as off-cut rather than counter, and it exists because your kitchen is not slab-shaped. Published figures put quartz at 12 percent and granite at 18. Quartz is manufactured to a rectangle with a consistent pattern, so the pieces nest tightly and any part of the slab can be used. Granite is cut from a quarried block, its edges are irregular, and the pattern varies across it, so parts of the slab are unusable and parts are unusable in the position you would want them.

Can a fabricator get my kitchen onto fewer slabs than this says?

Sometimes, and it is worth asking. This is a planning figure computed from your total area, while a fabricator lays your actual pieces out on the actual slab, and a good nest genuinely saves slabs that this arithmetic says you need. The reverse also happens: a vein you insist on matching across a joint can cost a slab this calculation does not see. Countertop Installers publishes the arithmetic so you know when to ask the question, not so you can hold a shop to it.

What happens to the leftover stone?

It becomes a remnant, and it is worth money. The off-cut from an ordinary kitchen is usually enough for a bathroom vanity top, a windowsill, a hearth or a set of matching shelves, and because it is the same slab it will match. Shops keep and resell remnants, which is entirely fair since they are storing and handling them, but the material is yours until you agree otherwise. Settle it in writing before the slab is cut rather than after it has left.

Will my counter need a seam?

If any single run is longer than the slab, yes, whatever a showroom tells you. HanStone Quartz, which manufactures in Ontario, publishes its jumbo at 65 by 130 inches, so 130 inches, or 10 feet 10 inches, is the longest single piece that can come off one. Granite slabs are quarried rather than made and are often smaller. A seam is a design decision when you are told about it before the quote and a complaint when you find out afterwards, so ask for the seam map early.

How many slabs of granite or quartz do I need?

Last updated: August 28, 2026By The Slab Desk

Square feet is not the question a stone yard answers. A slab is a fixed rectangle and your kitchen is not, so the answer is always a whole number reached by rounding up, and the rounding is where the money is. Two kitchens a few square feet apart can be a whole slab apart in price, and almost nothing on the web tells you where those boundaries fall.

Your kitchen, and the slab

Countertop area you actually need (square feet)The finished surface, not the slab. Waste is added below, not by you.

Slab size

58.68 usable sq ft per slab. Ask your fabricator which size the colour you have chosen actually comes in, because not every colour comes in every size.

Stone

Quartz is manufactured to a rectangle, so less is lost. Granite is quarried, so its edges are irregular and the published waste factor is higher.

Layout

Currently allowing 15% for off-cuts.

For 55 sq ft of finished countertop

2 slabs

55 sq ft plus 15% for off-cuts is 63.2 sq ft that has to fit on slabs. At 58.68 usable sq ft each that is 1.08 slabs, and nobody sells part of one, so it rounds up to 2.

Stone you will pay for: 117.4 sq ft
Off-cut left over92% of the last slab: 54.1 sq ft
Slabs alone, before anyone cuts them$40 to $60 per sq ft, material only (CAD), as published by Natural Stone City (Southern Ontario, 2026 guide): $4,694 to $7,042

You are just over a slab boundary, and that is worth a conversation

Only 4.6 sq ft of your job sits on slab number 2, and you are buying the whole thing. Shrinking the island overhang by a couple of inches, or moving to the next slab size up, can drop a whole slab off the order. Ask the fabricator to lay it out both ways before you commit, because they are the only person who can see whether it actually nests.

Do not throw the off-cut away

54.1 sq ft of stone you have already paid for is enough for a bathroom vanity top, a windowsill, a hearth or a set of matching shelves, and it is the same slab, so it matches. Shops keep remnants and resell them, which is entirely fair, but it is your material until you say otherwise. Put it in writing before the slab is cut.

This is a planning figure, not a cutting list. A fabricator lays your actual pieces out on the actual slab, and a good nest can save a slab that this arithmetic says you need. The number here is for reading a quote and for knowing when to ask the question.

The arithmetic, written out

Finished area, times one plus the waste factor, divided by the usable area of one slab, rounded up. That is the whole formula and it is worth doing on paper once so the shape of it is obvious: a 55 sq ft kitchen in granite is 55 times 1.15, which is 64.9 sq ft that has to fit on slabs. At 58.68 sq ft a jumbo, that is 1.11 slabs, which rounds up to two. The second slab is 93 percent off-cut.

Now do the same kitchen in quartz, where the published waste factor is 15 percent rather than 15. 55 times 1.15 is 61.6 sq ft, which is still 1.05 slabs and still rounds to two. That is the useful lesson: near a boundary, the material barely matters and a couple of inches of island overhang matters enormously. This is exactly the situation the tool flags, because it is the one moment where a homeowner has real leverage and almost never knows it.

One threshold on this page is not from a source and is labelled as such. The "you are just over a boundary" warning fires when the last slab is carrying less than 10 percent of the job. That figure was chosen here rather than published anywhere, and it decides only whether a piece of ADVICE appears. It never touches a price, a slab count or any number you are given. Every figure that does is in the table below with the source that published it.

The published specifications behind this tool

Specifications, not prices. The one money figure is slab supply, and it is Canadian.
Figure	Value	Published by
Standard (non-jumbo) quartz slab, 120 x 55 inches	45.83 sq ft per slab	QuartzCrafts, custom quartz sizing and waste guide
Jumbo quartz slab, 130 x 65 inches	58.68 sq ft per slab	QuartzCrafts, custom quartz sizing and waste guide
Super-jumbo slab, 138 x 79 inches	75.7 sq ft per slab	QuartzCrafts, custom quartz sizing and waste guide
Waste factor on a straightforward layout. Quartz Crafts publishes a good yield as 85 to 90 percent, meaning 10 to 15 percent of the slab becomes waste; the tool uses the UPPER end, because understating waste understates the slab count and that is the direction that leaves a reader short of stone.	15 percent	Quartz Crafts (custom quartz sizing, slab dimensions and waste guide)
Waste factor on a straightforward granite layout. No source found publishes a granite-specific waste figure, so this uses the same 10 to 15 percent band Quartz Crafts publishes for a good yield, at its upper end. Granite slabs are irregular and need calibration, so treat 15 percent as a floor rather than a ceiling.	15 percent	Quartz Crafts (custom quartz sizing, slab dimensions and waste guide)
Waste factor on a complex layout with many cuts, odd angles or vein matching. Quartz Crafts publishes yields dropping to 70 to 75 percent on a pattern-matched project, which is 25 to 30 percent waste; the tool uses the LOWER end, because overstating waste overstates the slab count and that is the direction that costs a reader money.	25 percent	Quartz Crafts (custom quartz sizing, slab dimensions and waste guide)
Jumbo quartz slab, HanStone Quartz (manufactured in Ontario), length	130 inches	HanStone Quartz Canada, colour spec page
Jumbo quartz slab, HanStone Quartz (manufactured in Ontario), width	65 inches	HanStone Quartz Canada, colour spec page
Jumbo quartz slab thicknesses offered by HanStone Quartz	2 cm, 3 cm cm	HanStone Quartz Canada, colour spec page
Natural granite slab, standard trade range (2600 to 3200 mm long by 1500 to 1900 mm wide)	102 to 126 by 59 to 75 inches	StoneTrades, stone slab sizes and yield guide
Yield lost to hand-arranged layouts. Dynamic Stone Tools states that manual nesting, meaning drawing pieces on paper or arranging cut-outs on the slab, consistently underperforms software nesting by 10 to 20 percent in yield.	10 to 20 percent	Dynamic Stone Tools (slab yield optimization guide)
Quartz slab, material only (no templating, fabrication or installation)	$40 to $60 per sq ft, material only (CAD)	Natural Stone City (Southern Ontario, 2026 guide)

Sources

Frequently asked questions

How many slabs of granite do I need for my kitchen?: Take the finished area you need, add the waste factor, divide by the usable area of the slab and round up. A standard quartz slab covers 45.83 square feet, a jumbo 58.68 and a super jumbo 75.7. Granite loses about 18 percent to off-cuts against quartz's 12, because it is quarried rather than manufactured and its edges are irregular. So a 55 square foot kitchen in granite is 55 times 1.18, which is 64.9 square feet, which is two jumbo slabs rather than one.
Why is the answer always a whole number?: Because nobody sells part of a slab. That sounds obvious and it is the most expensive thing on this page, because it means two kitchens a few square feet apart can be a whole slab apart in price. A job that spills two square feet over a boundary buys an entire extra slab and throws most of it away. Anything that returned 1.7 slabs would be arithmetically tidy and completely useless for planning.
What is a waste factor and why does granite have a higher one?: It is the share of a slab that ends up as off-cut rather than counter, and it exists because your kitchen is not slab-shaped. Published figures put quartz at 12 percent and granite at 18. Quartz is manufactured to a rectangle with a consistent pattern, so the pieces nest tightly and any part of the slab can be used. Granite is cut from a quarried block, its edges are irregular, and the pattern varies across it, so parts of the slab are unusable and parts are unusable in the position you would want them.
Can a fabricator get my kitchen onto fewer slabs than this says?: Sometimes, and it is worth asking. This is a planning figure computed from your total area, while a fabricator lays your actual pieces out on the actual slab, and a good nest genuinely saves slabs that this arithmetic says you need. The reverse also happens: a vein you insist on matching across a joint can cost a slab this calculation does not see. Countertop Installers publishes the arithmetic so you know when to ask the question, not so you can hold a shop to it.
What happens to the leftover stone?: It becomes a remnant, and it is worth money. The off-cut from an ordinary kitchen is usually enough for a bathroom vanity top, a windowsill, a hearth or a set of matching shelves, and because it is the same slab it will match. Shops keep and resell remnants, which is entirely fair since they are storing and handling them, but the material is yours until you agree otherwise. Settle it in writing before the slab is cut rather than after it has left.
Will my counter need a seam?: If any single run is longer than the slab, yes, whatever a showroom tells you. HanStone Quartz, which manufactures in Ontario, publishes its jumbo at 65 by 130 inches, so 130 inches, or 10 feet 10 inches, is the longest single piece that can come off one. Granite slabs are quarried rather than made and are often smaller. A seam is a design decision when you are told about it before the quote and a complaint when you find out afterwards, so ask for the seam map early.