Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Concrete needed (yd³)
3.26
Estimated cost
$538
Raw volume (cu ft)
80.0
80 lb bags
147
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter footing type.
- 2Enter trench length (ft).
- 3Enter trench width (in).
- 4Enter depth (in).
- 5Enter pier diameter (in).
- 6Enter number of piers.
- 7Enter ready-mix price ($/yd³).
- 8Read your concrete needed (yd³) on the right — it updates as you type.
- 9Hit Share to keep the scenario or send it to someone.
About this calculator
Footings carry the structure, so they get poured to code depth below the frost line. Enter the trench dimensions or the pier diameter and count to get your order volume.
Worked example
Using the values the calculator loads with:
Inputs
- Footing type: Continuous strip footing
- Trench length: 60 ft
- Trench width: 16 in
- Depth: 12 in
- Pier diameter: 12 in
- Number of piers: 8
- Ready-mix price: 165 $/yd³
Results
- Concrete needed (yd³): 3.26
- Estimated cost: $537.78
- Raw volume (cu ft): 80
- 80 lb bags: 147
What each field means
Inputs
- Footing type
- Pick the option that matches your situation — the maths changes per option. Choices: Continuous strip footing, Round pier holes.
- Trench length (ft)
- The trench length used in the calculation, measured in ft. Starts at 60 ft so you have a working example on load.
- Trench width (in)
- The trench width used in the calculation, measured in in. Starts at 16 in so you have a working example on load.
- Depth (in)
- The depth used in the calculation, measured in in. Starts at 12 in so you have a working example on load.
- Pier diameter (in)
- The pier diameter used in the calculation, measured in in. Starts at 12 in so you have a working example on load.
- Number of piers
- The number of piers used in the calculation. Starts at 8 so you have a working example on load.
- Ready-mix price ($/yd³)
- The ready-mix price used in the calculation, measured in $/yd³. Starts at 165 $/yd³ so you have a working example on load.
Results
- Concrete needed (yd³)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Estimated cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Raw volume (cu ft)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 80 lb bags
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the concrete footing calculator work?
Footings carry the structure, so they get poured to code depth below the frost line. Enter the trench dimensions or the pier diameter and count to get your order volume. The underlying maths is: Strip: Length × Width × Depth ÷ 27. Piers: π × r² × Depth × Count ÷ 27.
What do I need to enter?
7 values: footing type, trench length, trench width, depth, pier diameter, number of piers, and ready-mix price. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the concrete needed (yd³) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Concrete Footing Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/concrete-footing
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/concrete-footing" target="_blank" rel="noopener">Concrete Footing Calculator — RevenueLab</a> (2026).</p>
Source: [Concrete Footing Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/concrete-footing) (2026).