Slabs & footings
Concrete Calculator
Estimate a rectangular slab, pad, or footing and convert volume into complete premix bags using the yield on your product.
Preparing calculator...
How to calculate it
- Measure finished length and width.
- Enter compacted slab depth—not excavation depth.
- Use the yield printed on the exact bag size you plan to buy.
Frequently asked questions
How much extra concrete should I allow?+
Five to ten percent is common for small slabs because excavation and subgrade are rarely perfectly uniform.
Can I use this for structural foundations?+
Use it only for quantity planning. Foundation dimensions, reinforcement, mix design, and bearing requirements must follow local plans and codes.