How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Read cubic yards, bags and cubic feet results.
The For Concrete Footings Calculator lets you turn the dimensions of a footing—length, width and thickness—into the exact amount of concrete you’ll need. It instantly converts those measurements to cubic feet, then to cubic yards (the unit most suppliers use), and finally tells you how many 80‑lb bags of mix are required, based on the standard 0.6 ft³ per bag. Knowing the volume before you order prevents costly over‑orders or shortfalls that can delay a project. The results appear in three columns: Cubic Yards for ordering bulk, Bags for bagged mix, and Cubic Feet for quick on‑site checks. Use the numbers to compare quotes, schedule deliveries, and keep your budget on track. The calculator is free, works in any browser, and updates instantly as you change any dimension, so you can experiment with different footing sizes without leaving the page.
Pro tips
- Add about 10% extra for waste to the bag total.
- Round up the bag count to the next whole bag.
- Order a little extra if the subgrade is uneven or you expect spillage.
- Convert thickness from inches to feet before entering to avoid errors.
Real-life examples
- DIY homeowner sizing footings for a new patio slab.
- Contractor estimating concrete for deck support footings.
- Landscape designer calculating footings for a garden retaining wall.
Case study
Mike needed 3‑ft deep footings for a shed. He entered 6 ft × 4 ft × 36 in and the calculator showed 2.2 cubic yards, about 130 bags. He ordered exactly that amount, avoided a $150 over‑order and finished on schedule.