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Concrete Slab Cost Calculator

What a concrete slab costs, materials and placing.

Your measurementsEvery assumption editable01

Delivered. Short-load fees apply below about 3 yards.

Forming, placing, finishing and stripping. $4–8 is typical.

Excavation, gravel base and compaction.

Mesh or rebar with chairs.

Estimated costCalculated live02

Result

$1987–3312estimated

Midpoint $2650 — about $11.04 per sq ft

Slab area
240 sq ft
Materials
$668.89
Labour55% of the subtotal
$1320
Sub-base and excavation
$420
Subtotal
$2408.89
Contingency10%
$240.89
Midpoint estimate
$2649.78
Likely range±25%, the usual concept-stage spread
$1987 – $3312
Cost per sq ft
$11.04

This is a budgeting figure, not a quote. Regional labour rates vary by a factor of two or more across the country, and the same job priced in a busy season and a quiet one can differ by a third. Get three local quotes before committing to anything.

The range matters more than the midpoint. Construction estimating works to roughly ±25% until a scope is drawn and priced, and a single confident number would be pretending to a precision that does not exist at this stage.

Labour is usually the larger half and the more variable half. If the figure looks wrong, the labour rate is almost always the input to revisit first — material prices are far more consistent between regions than crews are.

Ready-mix is priced by the cubic yard while labour is priced by the square foot, so thickness and area pull in different directions. This handles both, plus the sub-base that most quick estimates ignore.

Why use this tool?What it does differently03

Why use this tool?

Two different units

Concrete by the yard, labour and prep by the square foot — which is why thickness and area affect the total differently.

Sub-base included

Excavation, gravel and compaction, which is real money and routinely left out.

Labour dominates

Around 55% of a typical slab. The concrete itself is the cheaper half.

Short-load fees flagged

Below about three yards, delivery surcharges can exceed the concrete cost.

How this worksThe method04

How this concrete slab cost calculator works

Volume in cubic yards drives the ready-mix cost; area in square feet drives placing, finishing, sub-base and reinforcement. Thickness therefore affects only part of the total, which is why going from four to six inches costs less than people expect.

Labour is typically the larger share — around fifty-five per cent on a standard slab. Concrete is a cheap material that is expensive to place well, and the finish quality is almost entirely down to the crew.

Below roughly three cubic yards most suppliers add a short-load fee, which on a small pour can exceed the value of the concrete itself. That is not modelled here, so add it for anything small.

How to use itStep by step05

How to use it

  1. Step 1: Enter the slab size

    Length, width and thickness. Four inches suits a patio, six a driveway.

  2. Step 2: Get a local ready-mix price

    Per cubic yard delivered. It varies more than most materials.

  3. Step 3: Set the labour rate

    $4 to $8 per square foot covers forming, placing and finishing in most areas.

  4. Step 4: Do not skip the base

    Prep is what stops a slab cracking. It belongs in the budget.

Example usageWorked figures06

Example usage

A 20 by 12 patio
240 sq ft at 4 in is 2.96 cubic yards. $669 materials, $1,320 labour, $420 sub-base — about $2,650 midpoint, or $1,987 to $3,312. That is $11.04 per square foot.
Going thicker
Six inches rather than four adds about $245 of concrete but no extra labour, taking it to roughly $2,920. Thickness is the cheap upgrade.
A decorative finish
Stamped or exposed aggregate can double the labour rate. Raising it to $11 takes the same patio to about $4,100.
Frequently asked questionsCommon questions07

Frequently asked questions

How much does a concrete slab cost per square foot?

Broadly $8 to $15 per square foot installed for a plain four-inch slab, including sub-base. Decorative finishes can double it.

How much does a cubic yard of concrete cost?

Commonly $150 to $200 delivered, varying by region and mix. Below about three yards expect a short-load surcharge on top.

Is labour or material the bigger cost?

Labour, usually by some margin — around 55 per cent of a typical slab. Concrete is cheap to buy and expensive to place well.

Does a thicker slab cost much more?

Less than you would think. Thickness only affects the concrete volume, not the labour, forming or finishing — so going from four to six inches adds maybe ten per cent to the total.

Why is sub-base included?

Because it is what stops the slab cracking, and because it is real money that quick estimates leave out. A slab on poor prep fails regardless of the mix.

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