Concrete Calculator: The Complete Guide
Estimate how much concrete your project needs. Enter the length, width, and thickness of your slab or pad to get the volume in cubic metres and yards, plus the number of 60 lb and 80 lb bags.
Who the Concrete Calculator is for
DIYers and builders pouring a slab, footing, patio, or pad who need volume and bag counts.
How to use the Concrete Calculator
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
Volume = length × width × thickness, converted to a consistent unit. Cubic yards = m³ × 1.308. An 80 lb bag yields about 0.6 ft³; a 60 lb bag about 0.45 ft³.
Features
- Cubic metres & yards
- 60 lb and 80 lb bag counts
- Imperial or metric
- Includes a waste tip
Estimating concrete
Concrete is ordered by volume — cubic yards in the US, cubic metres elsewhere — or in bags for small jobs. Multiply the area by the thickness to get the volume, then convert to bags using each bag's yield. Always add roughly 10% extra for spillage, uneven ground, and over-excavation.