Estimate a Concrete Slab: Cost, Yards and Bags
A 400 sq ft concrete slab at 4 inches costs $2,874 to $4,789 installed, about $7.18 – $11.97 per square foot. Type your own length, width and ZIP into the calculator to estimate yours.
LIKELY INSTALLED PRICE
$3,831
Our installed range for this 20×20 ft, 4-inch slab: $2,874 – $4,789 ($7.18 – $11.97 per sq ft)
In plain terms: that's about the size of a two-car garage pad, and roughly 49% of the price is the crew's labor.
- DIY materials
- $1,926
- Concrete
- 4.94 yd³
- Bagged mix
- 245 80-lb bags
- Delivery
- 1 truck
An estimate, not a bid. A contractor's price depends on your site, access and timing.
What changes the price
Where the money goes
- Materials$1,636
- Labor$1,557
- Overhead and profit (20%)$639
All 8 line items
| Item | Qty | Material | Labor | Total |
|---|---|---|---|---|
| Site setup, layout and cleanup | 1 job | $100 | $56 | $156 |
| Excavate and grade subgrade | 400 sqft | $0 | $444 | $444 |
| Forms, stakes and form release | 80 lf | $96 | $178 | $274 |
| Compacted crushed-stone base | 6.91 ton | $311 | $128 | $439 |
| 6x6 W1.4 welded wire mesh | 400 sqft | $147 | $89 | $236 |
| Ready-mix concrete, 3,500 psi, delivered | 5.19 yd3 | $902 | $115 | $1,017 |
| Place, screed and broom finish | 400 sqft | $20 | $518 | $538 |
| Sawn control joints | 40 lf | $60 | $30 | $90 |
| Subtotal × overhead and profit (20%) = midpoint | $3,831 | |||
National prices until you enter a ZIP.
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Compare a contractor's price with the range for these inputs.
What next
Get two or three quotes and compare them with $2,874 – $4,789. DIY: 245 bags or 5.19 yd³ of ready-mix.
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Turn this price into an estimate for your customer →Cost by thickness for 20x20 (400 sq ft)
4 in · patios, sheds
$2,874 – $4,789
4.94 yd³ · 245 bags · about $3,831
5 in · garages, driveways
$3,102 – $5,171
6.17 yd³ · 306 bags · about $4,137
6 in · shops, RV pads
$3,331 – $5,552
7.41 yd³ · 367 bags · about $4,442
Concrete slab cost per square foot
The example slab works out to $7.18 – $11.97 per square foot installed. Small pads cost more per foot because delivery and setup don't shrink with the slab. Large slabs cost less per foot for the same reason.
Price to pour a concrete slab: what's in it
The pour itself is only part of the price. Excavation, 6.9 tons of gravel, forms, 400 sq ft of wire mesh, finishing and cleanup are each a line in the table. Labor is priced from cement-mason wages for your area.
How much concrete for a slab
Volume is length times width times thickness, divided by 27 to get cubic yards. For this slab that's 4.94 yd³, or 5.19 yd³ once a waste margin is added. By bag it would be 245 80-lb bags.
Rebar or wire mesh
Mesh suits patios and sheds; rebar suits slabs under vehicles or walls. Switch the reinforcement selector and the steel line updates. The calculator lays out the rebar grid for you.
Heated slab, removal and slab jacking
Radiant heat tubing, tearing out an old slab and lifting a sunken one are separate jobs with separate prices. Removal can be added in the calculator. Heating and slab jacking need a specialist's quote.
Estimate or bid?
Every figure here is an estimate from public wage data and estimated material prices. It isn't a bid. Use it to budget and to spot quotes that leave something out.
DIY vs pro for this 20x20 pour
Materials alone come to $1,926, about 50% of the $3,831 midpoint contractor price. The difference is $1,905 of labor, equipment, delivery and contractor overhead across 8 line items. At 5.19 yd³ with waste the pour fills 1 mixer truck, so ready-mix is the practical route even for a DIY pour.
Cost by slab size (dedicated pages)
- 10x10 concrete slab cost$941 – $1,569100 sq ft · 1.23 yd³ at 4 in
- 10x12 concrete slab cost$1,094 – $1,823120 sq ft · 1.48 yd³ at 4 in
- 12x12 concrete slab cost$1,279 – $2,132144 sq ft · 1.78 yd³ at 4 in
- 10x20 concrete slab cost$1,625 – $2,708200 sq ft · 2.47 yd³ at 4 in
- 12x20 concrete slab cost$1,922 – $3,203240 sq ft · 2.96 yd³ at 4 in
- 20x20 concrete slab cost$2,874 – $4,789400 sq ft · 4.94 yd³ at 4 in
- 24x24 concrete slab cost$4,848 – $8,080576 sq ft · 7.11 yd³ at 4 in
- 20x30 concrete slab cost$4,983 – $8,306600 sq ft · 7.41 yd³ at 4 in
- 20x40 concrete slab cost$6,562 – $10,936800 sq ft · 9.88 yd³ at 4 in
- 30x30 concrete slab cost$7,324 – $12,206900 sq ft · 11.11 yd³ at 4 in
- 30x40 concrete slab cost$9,664 – $16,1061,200 sq ft · 14.81 yd³ at 4 in
- 30x50 concrete slab cost$12,004 – $20,0061,500 sq ft · 18.52 yd³ at 4 in
- 40x40 concrete slab cost$12,766 – $21,2761,600 sq ft · 19.75 yd³ at 4 in
- 40x60 concrete slab cost$18,970 – $31,6172,400 sq ft · 29.63 yd³ at 4 in
Compare with the next sizes
Frequently asked questions
How much does a concrete slab cost?
The example 400 sq ft slab costs $2,874 to $4,789 installed. Your own figure depends mostly on size, thickness and local wages, so enter those above.
How do I estimate a concrete slab myself?
Multiply length, width and thickness in feet, divide by 27, and add a waste margin. Then price concrete, base, steel, forms and labor. The calculator does all of this in one step.
Is it cheaper to pour a slab yourself?
On materials, yes: the DIY line here is $1,926. Past a few yards, ready-mix and a finishing crew are usually faster and cost little more.
Where does the labor rate come from?
From the Bureau of Labor Statistics wage survey for cement masons and concrete finishers. The Data used box names the exact release and geography.
Does the estimate include permits?
No. Permit fees vary by city and aren't in the figure. Check with your building department before you excavate.
For contractors
Quoting concrete for customers?
The free estimating app opens with a sample concrete job priced the same way. Read more about concrete estimating software.