How Much Is a 20x20 Concrete Slab?
A 20x20 concrete slab costs $2,874 to $4,789 installed at 4 inches, which is $7.18 – $11.97 per square foot. The calculator below reprices it as a patio, a garage floor or with your own ZIP.
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
- Typical use
- A backyard patio or a compact one-to-two-car garage floor.
- Thickness
- 4 inches with mesh as a patio; 5 inches or more with rebar if it will carry vehicles.
- Planning note
- A 20x20 needs control joints dividing it into panels; ask the contractor where they will saw them.
How much does a 20x20 concrete patio cost?
As a broom-finished patio the price is the $2,874 to $4,789 shown above. A stamped or colored finish raises it; switch the finish in the calculator to compare.
Cost of a 20 x 20 slab as a garage floor
Under cars, most builders pour thicker and use rebar instead of mesh. Change the thickness to see what that does to the concrete and the price.
Concrete for a 20x20 slab
At 4 inches the slab is 4.94 yd³, or 5.19 yd³ ordered, on 1 truck. By bag it would be 245, which is why this size is almost always a truck pour.
20x20 concrete slab under a garage
If walls will sit on this slab, the edge is usually poured deeper to carry them. That thickened edge is priced on the garage calculator, not here.
Reading the 20x20 range
The range comes from estimated material prices and wage data. It isn't a quote, but a bid far outside it deserves questions.
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.
Other popular slab sizes
- 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
- 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
Compare with the next sizes
Garage concrete slab cost calculatorAll slab sizes and the full calculator
Frequently asked questions
How many yards of concrete is a 20x20 slab?
4.94 yd³ at 4 inches before waste. Most crews order a bit extra, and the calculator shows that as 5.19 yd³.
Is a 20x20 garage big enough for two cars?
It fits two small cars with little room to open doors. Many owners who plan two cars go to 24x24; compare that page's price.
How long does a 20x20 slab take to install?
Prep takes one to three days, depending on digging and forms. The pour and finish usually happen in one morning.
What adds the most to a 20x20 price?
Thickness and finish. Removing an old slab also adds a lot, so enter the square footage in the calculator if you have one.
For contractors
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