What you get
Every calculator the app offers, on every screen of every device, even when there's no signal.
All five calculators
Rectangular slab, circular slab, slab area for irregular pours, circular columns and post holes — with optional post-profile displacement.
Imperial and metric
Type 14ft 2 1/16in or 0.15m — the inputs accept both. Switch the output between cubic yards, cubic feet and cubic metres at any time.
Save projects, work offline
Calculate without signal on remote sites. Save jobs and revisit them later. History across every calculation you've run.
Why a phone app and not just the web
The web calculators on this site are free and fully featured — no install required if all you need is a quick number. The app earns its place on a tradie’s phone with the things a browser can’t do well:
- Reliability when it matters. Concrete trucks arrive on time and don’t wait. The app works without signal, on a basement pour or out past the last cell tower.
- Saved jobs. Set up a job once with all its dimensions, come back to it on every visit. No copy-pasting from Notes.
- History. Every calculation gets logged automatically. Quote a job from last month without re-measuring.
- One screen, the trade. No tabs, no banners, no cookies popups. Just the calculators.
Built for working tradies
We built Concrete Calculator because the existing options were either thin web pages with awful UX or one-trick-pony apps that did slabs and nothing else. The five calculator types here cover the overwhelming majority of residential and small-commercial concrete pours.
The math follows ACI 318 — the same standard used by ready-mix plants and commercial estimators — so the volume the app gives you matches what your supplier expects when you order. The 10% buffer on every result is the conservative end of the 5–10% ACI recommendation; if you’ve never been short on a pour you’ll know why we picked 10.
Free, no ads, no nonsense
The app is free to download and free to use. There are no ads in the calculators. No upsell modal between you and the result. No data collected beyond what’s needed to keep the app working.
If you want to support the project, the best way is to leave a review on the App Store after a job goes well — that helps other tradies find the app. We read every review.
Get it now
The fastest way to start is to install the app and try the slab calculator on your next pour. It takes ten seconds.