Concrete Calculator
Cubic yards, bags and cost for any pour — slab, footing, wall, column, stairs or curb. Updated live as you type.
Shape
Waste factor
Concrete needed (waste in)
5.43 yd³
146.7 ft³ · 4.15 m³
Bags (rounded up)
245
80 lb
326
60 lb
392
50 lb
489
40 lb
- Ready-mix (delivered)
- $739 – $1,207
- Bagged (80 lb)
- $1,348 – $2,205
- Installed (slab)
- $2,200 – $4,800
The universal concrete calculator
Most concrete calculators only do a slab — and the manufacturers' tools only calculate their own bags. This one handles every common pour and gives you the three numbers that matter for each: how much concrete in cubic yards, how many bags at any size, and what it costs as ready-mix or bagged.
How to calculate concrete volume
Concrete is ordered by the cubic yard (27 ft³). Find the volume of your shape, then divide by 27:
- Slab / floor: width × length × thickness.
- Footing: length × width × depth.
- Wall: length × height × thickness.
- Round column / tube: π × radius² × height.
- Stairs: the filled step profile × width.
- Curb & gutter: the cross-section × length.
Enter dimensions in feet and inches — the calculator converts, adds waste, and rounds bags up.
Concrete bag yields (quick reference)
| Bag size | Yield (ft³) | Bags per yd³ |
|---|---|---|
| 80 lb | 0.600 | 45 |
| 60 lb | 0.450 | 60 |
| 50 lb | 0.375 | 72 |
| 40 lb | 0.300 | 90 |
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: