How to use it
- Enter the footing length in feet.
- Enter the width in feet.
- Enter the thickness in inches.
- Read the cubic feet, cubic yards, and bag count results.
What it does – The Concrete Footings Calculator takes the length, width, and thickness you enter and instantly converts them to the volume you need in cubic feet, then to cubic yards and the number of 80‑lb bags of mix. Why it matters – Knowing the exact volume prevents ordering too little (causing delays) or too much (wasting money). How to read the results – Cubic feet is the raw volume of your footing. Divide by 27 to get cubic yards, the unit most suppliers quote. Divide cubic feet by 0.6 to see how many bags of mix you’ll need. You can also add a 10% waste factor to the bag count for cuts and spillage. The calculator updates instantly, so you can experiment with different footing dimensions until you hit your budget target.
Pro tips
- Add 10% extra bags for waste and spillage.
- Round up the bag count to the nearest whole bag before ordering.
- Order slightly more than calculated to avoid shortfalls on site.
- Convert thickness from inches to feet by dividing by 12.
Real-life examples
- A homeowner building footings for a 12‑ft patio.
- A contractor estimating concrete for a new driveway.
- A DIYer planning a shed foundation and needing exact material quantities.
Case study
Mike needed footings for a 10 × 8 ft shed. Using the calculator he saw he required 0.9 yd³ of concrete, about 42 bags. He ordered 45 bags, avoided a second delivery, and finished the foundation two days early.