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ACI 318
Validated against the standard.
PDF export
Pro-only. Generate professional reports.
$2.99 Pro
Lifetime unlock. No subscriptions.
How it works
Enter your values
Type in your inputs — the app fills code tables and constants for you, so there's nothing to look up.
Get a code-checked result
Instant answer with a clear PASS / FAIL and the exact ACI 318 reference behind every number.
Save & export
Keep a history of calculations and export a clean PDF report to share or attach to a permit (Pro).
What this calculator does
For general contractors, concrete is one of the easiest line items to get wrong — and short-ordering means a cold joint and a return truck charge. This app converts any pour (slab on grade, footing, grade beam, foundation wall, pier) into cubic yards and ready-mix or bag quantities, with a waste allowance built in.
The formula
Cubic yards = length (ft) × width (ft) × thickness (ft) ÷ 27
Combine multiple shapes — a slab plus its thickened edge, or a wall plus footings — and the app totals them, then adds your chosen waste percentage.
Worked example
A 24 x 24 ft garage slab at 4 in (0.333 ft): 24 × 24 × 0.333 ÷ 27 = 7.1 yd³. Add 5–10% for subgrade irregularity and order 8 yd³ of ready-mix.
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Concrete FAQ
How is concrete volume calculated?
Length times width times thickness, all in feet, divided by 27 to convert cubic feet to cubic yards — the unit ready-mix is ordered in.
How much waste should I add for a pour?
Five to ten percent is typical to cover subgrade variation, spillage, and over-excavation. The app lets you set the allowance.
Can it combine shapes?
Yes. Add slabs, footings, walls, and piers together and it totals the cubic yards for the whole pour.
Does it work offline?
Yes, it runs 100% offline with no account. Free with rewarded ads; a one-time $2.99 Pro unlock adds PDF export and saved history.
Get Concrete Calculator on your phone
Free with rewarded ads · $2.99 lifetime Pro · iOS & Android. Works 100% offline on the job site.