Concrete slab cost calculator
Last updated: By ConcreteFinder Research Team
Slab quotes are hard to compare because two contractors can price two different products and call them the same thing. One is a 4 inch pad on whatever is there; the other is 6 inches on compacted A-gravel with a mesh grid and a vapour barrier. Set what you actually want below and the calculator prices the parts separately, so you can put a quote next to it line for line.
What will a concrete slab cost?
Estimated installed cost for 400 sq ft
$6,000 to $12,400
- Plain broom-finish pad, installed ($15 to $31 per sq ft across three Ontario sources)
- $6,000 to $12,400
- Works out at, per square foot
- $15.00 to $31.00
Excludes 13 percent HST and any building permit. A detached garage, a slab that carries a structure, and underpinning all need permits in Toronto and engineered drawings in some cases; a plain patio-level pad usually does not.
Why the sources disagree by two to one
Nice Guy Concrete quotes $15 to $25 per square foot for a shed pad. Compare Paving Contractors quotes $26 to $31 for a garage slab. Both are current, both are Canadian, and neither is wrong. A shed pad carries a shed; a garage slab carries a building, a vehicle and in Compare Paving's case insulated formwork and drainage. The band on this page spans both because the honest answer to a homeowner is that the spec, not the market, is what moves the number.
2AZ Group's example sits lower still: $3,090 to $4,340 for a 20 by 20 pad at 4 inches, which is $7.73 to $10.85 per square foot. That is a builder pricing his own materials and crew on a thin slab, and it is a useful floor to know about, but it is not what a homeowner is quoted, so it is shown as a comparison rather than folded into the range.
The one figure everyone agrees on is that removal costs more than pouring. Strong Basements prices a basement pour from $10 a square foot and breaking out the old floor from $14; for a garage it is $15 against $20.
What goes under the slab
Everything that makes a slab last is buried before the pour, and every one of those items is a line a cheaper quote can drop. Strong Basements prices them individually: gravel bedding at $5 per square foot, wire mesh at $1, a steel rebar grid from $8, and 2 inch R10 rigid foam from $4. A quote that is $6 a square foot under another one is usually missing two of those four.
Concrete volume for the pour itself is small money by comparison. A 400 square foot pad at 5 inches is about 4.7 cubic metres, which the concrete calculator puts at roughly $825 to $1,650 delivered. Everything else on the invoice is labour, machine time, disposal and the things under the slab.
ConcreteFinder tracks 10 companies doing garage pads and slabs across the Greater Toronto Area. Ask each of them to quote the same thickness, the same base depth and the same reinforcement, in writing, or the numbers are not comparable.
Frequently asked questions
How much does a concrete slab cost in Ontario?
An outdoor pad runs $15 to $31 per square foot installed depending who you ask. Nice Guy Concrete quotes $15 to $25 for a shed pad, The Art of Concrete quotes $15 to $30 with a plain broom-finished pad starting near $20, and Compare Paving Contractors quotes $26 to $31 for a standard garage slab.
What does a 20 by 20 garage pad cost?
At the $15 to $31 band that is $6,000 to $12,400 for 400 square feet. 2AZ Group publishes a lower worked example for the same size, $3,090 to $4,340 for a 4 inch slab, which is a builder's cost breakdown rather than a retail quote. Compare Paving prices a 24 by 24 slab at $16,612 with excavation and formwork in and a pump $1,030 extra.
How much does a basement concrete floor cost?
Strong Basements in Etobicoke publishes starting prices rather than ranges: a 4 inch basement pour from $10 per square foot, taking out the existing floor and digging 7 inches from $14, gravel bedding at $5, wire mesh at $1 and 2 inch R10 foam from $4. A garage floor is a 6 inch pour from $15 and removal from $20.
How thick should a concrete pad be?
The Art of Concrete describes a proper Ontario pad as 5 to 7 inches over A-gravel, and 6 to 8 inches for heavy-duty use. Strong Basements pours a basement floor at 4 inches and a garage floor at 6. A price quoted against a 4 inch slab is not comparable to one quoted against 6.
Why does removing the old slab cost more than pouring the new one?
Because breaking, lifting and tipping concrete is slower and heavier than placing it, especially indoors where every bucket comes out by hand. Strong Basements prices a basement floor pour from $10 per square foot and its removal from $14, and a garage floor pour from $15 against removal from $20.
Do I need a permit for a concrete pad in Toronto?
A slab that carries a structure does. A detached garage, an addition and any underpinning all need a building permit, and some need engineered drawings. A plain ground-level patio pad that carries nothing usually does not. Check with Toronto Building before the forms go in, not after.
Sources
Every rate above was re-read from its source on 2026-08-25. Canadian dollars, before 13 percent HST. Dataset July 2026.
- Nice Guy Concrete - Concrete Shed Pads (Halton, Peel, Hamilton)
- The Art of Concrete - The Cost of a Concrete Pad in Ontario
- Strong Basements - Basement and garage concrete floor pricing (Etobicoke)
- Compare Paving Contractors - Concrete Slab for a Garage Price Guide
- 2AZ Group - The Real Cost of Concrete Work in the GTA in 2026
- Nice Guy Concrete - 2026 Concrete Driveway Cost Ontario (slab tearout)
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