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Concrete Slab Cost Calculator — Price per Square Foot

Estimate what a concrete slab will cost, line by line. Compare DIY against a contractor, adjust every price, and get a cost per square foot instantly.

Enter the size of the pour and this concrete slab cost calculator prices the concrete, gravel, steel, forms and labour separately, so you can see where the money goes.

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Tax is applied to materials only, not labour.

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Needed when a truck cannot reach the pour.

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These are rough national-average starting points, not quotes, and local prices vary widely. Last updated October 1, 2026.

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Enter your slab size to see a full cost breakdown.
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Concrete Slab Cost by Size

All rows are 4 in thick with a broom finish, 10% waste, no sales tax and the default prices, as of October 1, 2026. Tap a row to load it into the form.

Slab sizeArea (sq ft)DIY estimateContractor estimatePer sq ft (contractor)
100$726$1,076$10.76
144$976$1,504$10.44
240$1,516$2,436$10.15
320$1,852$3,112$9.73
400$2,288$3,888$9.72
576$3,242$5,594$9.71
1200$6,591$11,641$9.70

What Drives Slab Cost

FactorTypical swingWhy
Thickness4 in to 6 in adds about 8% to 12% to the totalOnly the concrete line grows with depth. Gravel, rebar, excavation and labour are priced by area, so a 50% thicker slab raises the whole bill far less than 50%.
Finish type$0 to $12 per sq ft extraA broom finish is the baseline. Stamping, polishing and exposed aggregate need extra materials, sealers and specialist crews, and the labour for them is the expensive part.
Site access$0 to $900 or moreA truck chute reaches only about 10 to 15 ft past the truck. Beyond that you pay for a pump, or for extra hands wheelbarrowing about 70 loads for an 8 yd³ pour.
Sub-grade condition$0.50 to $3 or more per sq ftSoft clay, fill or organic soil has to be dug out and replaced with compacted stone. Rock, tree roots and poor drainage add machine time and spoil to haul away.
ReinforcementAbout $0.70 per sq ft at 16 in centresClosing the grid from 16 in to 12 in puts about a third more steel in the same area. Heavy loads justify it; a patio on firm ground often does not.
Slab sizeAbout $1 per sq ft between 100 and 1,200 sq ftShort-load fees, minimum call-out charges and setup time are fixed costs. Spread over 100 sq ft they dominate; spread over 1,200 sq ft they nearly vanish.
Region20% to 40% either wayReady-mix prices follow local aggregate supply and haul distance, and labour follows local wages. Dense metro areas and remote sites both sit above the national average.
Season5% to 15%Cold-weather pours need blankets, heated water or accelerators. Peak summer demand books crews out, so quotes tend to be lower in the shoulder seasons.

How much does a concrete slab cost

Contractors quote slabs by the square foot because nearly every cost in the job follows the footprint rather than the volume. The gravel, vapour barrier, rebar grid, excavation and finishing labour all scale with area, and only the concrete itself scales with thickness. One rate per square foot lets a crew price a patio and a garage from the same rate card, and lets you compare three quotes without redoing the geometry. At the default prices here, a hired 4 in broom-finished slab lands at roughly $9.70 to $10.80 per square foot, and the same slab done yourself at roughly $5.50 to $7.30. This page works out the concrete volume from your dimensions, but if you want the quantities behind each line, work out the volume first and compare the gravel and rebar totals.

Here is a full example. A 24 × 24 ft slab at 4 in with a broom finish has an area of 576 sq ft and a perimeter of 96 ft. The volume is 576 × 0.333 = 192 cubic feet, or 7.11 cubic yards, and 7.82 with a 10% allowance. At $140 a yard the concrete is $1,095. That is above the short-load threshold, so there is no extra fee. Four inches of compacted stone is about 10 tons, and ordering 20% more to allow for compaction gives 11.9 tons × $45 = $538. The vapour barrier is 634 sq ft × $0.15 = $95, rebar at 16 in centres is 912 ft × $0.45 = $410, and excavation is 576 × $1.50 = $864. Together that is $3,002 of materials and site work.

Doing it yourself adds forms and stakes at 96 ft × $2.50 = $240, for a total of $3,242, or $5.63 per square foot. A contractor replaces the forms with labour at 576 × $4.50 = $2,592, for a total of $5,594, or $9.71 per square foot. Those are planning figures from editable national averages, so swap in the numbers from a real quote before relying on them.

Small slabs cost more per square foot than large ones. A 10 × 10 ft pad needs only about 1.36 cubic yards with waste, which is under the usual minimum load, so the $100 short-load fee applies and lifts the hired price to about $10.76 per square foot. A 30 × 40 ft pour spreads the same fixed costs across 1,200 square feet and falls to about $9.70. Contractors also charge a minimum call-out, and setting up forms, screeds and finishing tools takes the same time on a small pad as a large one.

What DIY really saves is labour, and the saving is large: about $2,352 on the example above, or 42% of the contractor price. What it costs you is time and risk. At an assumed $35 an hour that saving pays for roughly 67 hours of work, and the concrete will not wait for you. You have an hour or two to place, screed, float and edge it before it stiffens, and finishing is a skill with no undo. A badly finished slab is usually fixed by grinding or breaking it out, which erases the saving, so many owners pour the base and forms themselves and hire only the finishing crew.

Sales tax, site access and awkward shapes

In most US states, sales tax applies to materials such as concrete, gravel and rebar, while labour on new construction is not taxed when it is billed separately. That is why the tax rate field applies only to material lines. Some states tax the whole contract or treat a lump-sum job differently, so ask your supplier or state revenue office. To see what a rate adds to a materials order on its own, run the figures through the Sales Tax Calculator for a materials order.

Access can change the bill more than the mix does. A truck chute reaches only about 10 to 15 ft, and beyond that you need a pump, commonly a flat hire fee of a few hundred dollars plus a per-yard charge, or enough helpers to wheelbarrow roughly 70 loads for an 8 cubic yard pour. Switch the pump on when the truck cannot get close, then enter the fee from your quote.

This page prices one rectangle. For an L-shape, a T-shape or two separate pads, add each piece with the multi-section feature in the Concrete Slab Calculator, then enter a rectangle of the same total area here and check the forms and perimeter lines by hand.

How to use this calculator

  1. 01Enter the slab length and width, choosing a unit for each. Mixed units are fine.
  2. 02Pick the thickness with the quick-pick buttons and choose a finish. A broom finish is the standard baseline.
  3. 03Tick the work that applies: sub-base, rebar, excavation and, only if a truck cannot reach the pour, the pump.
  4. 04Open Adjust prices and replace the national-average defaults with figures from a real local quote, then add your sales tax rate.
  5. 05Switch between DIY and Hire a contractor, read the comparison, and take the breakdown to at least three local suppliers.

Common questions

How much does a concrete slab cost per square foot?
A 4 in broom-finished slab on a gravel base with rebar commonly costs about $8 to $12 per square foot when a contractor does everything, and about $5 to $7 per square foot in materials and site work when you do the labour yourself. Small slabs sit at the top of the range and large ones at the bottom. Local prices vary widely, so treat these as planning ranges.
How much does a 24x24 concrete slab cost?
A 24 ft × 24 ft slab is 576 sq ft. At 4 in thick with a gravel base, rebar and a broom finish, a contractor price commonly falls between about $5,000 and $6,500, and the DIY cost between about $3,000 and $3,800. The calculator defaults land inside those ranges, at roughly $5,594 hired and $3,242 DIY.
How much does a 10x10 concrete slab cost?
A 10 ft × 10 ft slab at 4 in thick commonly costs about $900 to $1,300 hired and about $650 to $850 if you do the labour. The per-square-foot price is high for a pad this small because the order falls under most suppliers' minimum load, so a short-load fee applies. Local quotes can sit outside this range.
Is it cheaper to pour a concrete slab yourself?
Yes, usually by 35% to 45% of the contractor price, because the saving is the labour. On a 576 sq ft slab that is often $2,000 to $2,700. The trade-off is time and risk: you have an hour or two to place and finish the concrete before it stiffens, and a poor finish is expensive to correct.
Why do small concrete slabs cost more per square foot?
Several costs do not shrink with the slab. Suppliers charge a short-load fee on small orders, contractors apply a minimum call-out charge, and forms, screeding and finishing take almost as long to set up for a small pad as a large one. A slab of 100 sq ft commonly costs about $1 more per square foot than one of 1,200 sq ft.
What is a short load fee for concrete?
It is a flat charge, commonly $75 to $150, that suppliers add when an order is smaller than a minimum load, often somewhere between 3 and 5 cubic yards. It covers the truck, driver time and washout, which cost the same whatever the volume. The calculator applies it under the threshold set in Adjust prices, and you can change both figures.
Does slab thickness change the cost much?
Less than most people expect. Going from 4 in to 6 in adds 50% more concrete, but gravel, rebar, excavation and labour are priced by area and stay the same, so the total typically rises only about 8% to 12%. Extra thickness is often cheap insurance for driveways and garage floors.
How much does stamped concrete add to the cost?
Stamped concrete commonly adds about $6 to $12 per square foot on top of a plain slab, and the calculator uses $8 as its default. On a 576 sq ft slab that is roughly $3,500 to $7,000 extra. Most of it is specialist labour, sealers and colour, which is why stamping is rarely a first DIY project.
Is sales tax charged on concrete labour?
In most US states, sales tax applies to materials such as concrete, gravel and rebar, while labour billed separately on new construction is not taxed. Some states tax the full contract or treat lump-sum jobs differently, so confirm with your supplier or state revenue office. The calculator applies your tax rate to material lines only.
What is not included in a concrete slab quote?
Quotes often exclude permits and inspection fees, demolition and disposal of existing concrete, utility relocation, tree and stump removal, drainage work, and any extra excavation caused by soft ground or rock. Pump hire and winter protection may also be separate lines. Ask each contractor for a written list of inclusions, and compare at least three quotes.
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Every figure is a planning estimate built from user-editable national-average defaults, not a quote. It excludes permits, inspection, demolition of existing concrete, utility relocation and unusual site conditions. Always get at least three local quotes before committing. Last updated: October 1, 2026.