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SlabCosts
Prices updated January 2026

25×25 Concrete Slab Cost

A 25×25 slab covers 625 square feet. Here's the concrete, bags and cost for 2026 — a common size for a garage.

Concrete (4", waste in)

8.49 yd³

382 × 80 lb bags

Materials (ready-mix)

$1,121 – $1,788

delivered, 4" slab

Installed by a pro

$3,438 – $7,500

4" slab, national average

25×25 slab cost calculator

Adjust thickness, waste or region — the cost updates live.

Waste & region

Order extra for spillage & uneven subgrade. 10% is typical.

Installed cost estimate

$3,438 – $7,500

625 sq ft · 8.49 yd³ concrete

Bags of concrete needed (rounded up)

382

80 lb

510

60 lb

612

50 lb

764

40 lb

Ready-mix (delivered)
$1,121 – $1,788
Bagged mix (80 lb, DIY)
$2,101 – $3,438
Installed by a pro
$3,438 – $7,500

Estimate only — not a quote. Bag counts are rounded up and include a 10% waste allowance.

Installed $3,438 – $7,500

25×25 slab cost by thickness

Thickness Concrete 80 lb bags Ready-mix Installed
4" 8.49 yd³ 382 $1,121 – $1,788 $3,438 – $7,500
5" 10.61 yd³ 478 $1,326 – $2,016 $3,906 – $7,969
6" 12.73 yd³ 573 $1,591 – $2,419 $4,375 – $8,438

Includes a 10% waste allowance; bag counts rounded up. National US averages, January 2026.

You'll also need

Sized for this exact slab — tap any item to open its calculator with your measurements already filled in.

Gravel base

8.87 yd³

4" compacted base under the slab

≈ $266 – $577

Open calculator
Rebar

43 sticks

#4 bar, 18" grid (34 bars)

≈ $301 – $559

Open calculator
Bedding sand

1.93 yd³

~1" leveling layer

≈ $54 – $112

Open calculator

25×25 concrete slab: what to expect

A 25×25 slab covers 625 square feet. At the standard 4" thickness it takes about 8.49 cubic yards of concrete once you allow 10% for waste, which is roughly 382 × 80 lb bags if you mix by hand. Stepping up to 6" — sensible if it'll carry a vehicle — raises that to about 12.73 cubic yards.

Budget around $3,438 – $7,500 to have a 4" slab this size poured and finished by a contractor, or roughly $1,121 – $1,788 in ready-mix if you're doing the labor yourself. On top of the concrete you'll need about 8.87 yd³ of gravel base and 43 sticks of rebar.

Compare nearby sizes

Planning something bigger or smaller? Jump straight to the cost for a nearby size.

Size Concrete (4") 80 lb bags Installed cost
20×24 6.52 yd³ 294 $2,640 – $5,760
24×24 7.82 yd³ 352 $3,168 – $6,912
20×30 8.15 yd³ 367 $3,300 – $7,200
24×30 9.78 yd³ 440 $3,960 – $8,640
20×40 10.86 yd³ 489 $4,400 – $9,600
30×30 12.22 yd³ 550 $4,950 – $10,800

See all common slab sizes →

Prices updated January 2026 National US averages · reviewed quarterly

Volumes use standard bag yields and a 10% waste allowance; costs are national US averages that vary by region, mix and finish. See our methodology for exactly how each figure is worked out, or check the reference sources:

Slab cost by project

Concrete Slab Cost Cost per sq ft + calculator Garage Slab Cost Typical 20×20 / 24×24 Driveway Slab Cost Concrete vs asphalt Patio Slab Cost 10×10 to 20×20 Shed Base Cost Small pads

Frequently asked questions

How much does a 25×25 concrete slab cost?
A 25×25 slab (625 sq ft) costs about $3,438 – $7,500 installed at 4" thick in 2026, or $4,375 – $8,438 at 6". DIY in materials, the ready-mix runs about $1,121 – $1,788 at 4".
How many yards of concrete for a 25×25 slab?
At 4" thick a 25×25 slab needs about 8.49 cubic yards including 10% waste (7.72 yd³ net). At 6" it needs about 12.73 cubic yards.
How many bags of concrete for a 25×25 slab?
At 4" you'd need roughly 382 × 80 lb bags, 510 × 60 lb bags or 764 × 40 lb bags. That's a lot of mixing — past about a cubic yard, ready-mix is usually cheaper and easier.
What base and rebar does a 25×25 slab need?
Plan on about 8.87 cubic yards of compacted gravel base and roughly 43 sticks of #4 rebar on an 18" grid. The "You'll also need" cards size these for you.