Concrete slab or patio calculator
Concrete by the yard or the bag, gravel base, forms, reinforcement and curing for a slab or patio, from its area and thickness.
An estimate of the materials a job takes, worked out in your browser: check it against the job, and against your local code where it matters. Nothing you type leaves this page.
Put in the job's numbers and choices, and the list below follows them.
What it takes
Worked out for Slab area 300 sq ft, Slab edge 70 ft, Thickness 4 in, Reinforcement: #4 rebar at 18 in, Concrete: Ready-mix truck.
Concrete
- Ready-mix concrete 4.25 cu yd Slab area 300 sq ft at Thickness 4 in in deep, in cubic yards: 3.7 cu yd; plus 10% waste: 4.07; rounded up to packs of 0.25: 4.25. Ordered to the quarter yard.
- Crushed gravel base 5 cu yd Slab area 300 sq ft at 4 in deep, in cubic yards: 3.7 cu yd; plus 10% waste: 4.07; rounded up to whole cu yd: 5. A 4 in compacted base.
- Curing compound, 5 gal 1 pail Slab area 300 sq ft, one per 1000: 0.3 pail; rounded up to whole pail: 1.
Left out: Concrete, 80 lb bag (only when Concrete is 80 lb bags).
Forms and joints
- Form board, 2x4x8 10 each Slab edge 70 ft at 8 a piece: 8.75 each; plus 10% waste: 9.63; rounded up to whole each: 10.
- Form stakes, 18 in 24 each Slab edge 70 ft, one per 3: 23.33 each; rounded up to whole each: 24.
- Expansion joint, 4 in x 10 ft 7 each Slab edge 70 ft at 10 a piece: 7 each.
Reinforcement
- #4 rebar, 20 ft 22 each ((Slab area 300 sq ft × 2) ÷ 1.5) ÷ 20: 20 each; plus 10% waste: 22.
- Rebar chairs, 100 ct 3 bag Slab area 300 sq ft, one per 100: 3 bag.
Left out: Welded wire mesh, 5 x 150 ft roll (only when Reinforcement is Wire mesh); Concrete fiber, 1 lb bag (only when Reinforcement is Fiber).
Labor
- Concrete flatwork 300 sq ft Slab area 300 sq ft: 300 sq ft.
What it leaves out
- Excavation deeper than the base
- A pump truck
- Permits and inspection fees
- Engineering
The same calculator in SMG Tools
In SMG Tools this calculator fills its numbers from the client's site measurements, prices every line from your own Price Book, checks the margin against your target, and carries the lines onto the proposal, the job's plan and the purchase order. It is one of the ready-made calculators SMG Tools sets up for concrete and hardscape, and calculators are on every plan.