Concrete Footing Calculator
This concrete footing calculator finds the concrete volume for strip footings and pad footings, plus an optional foundation wall on top of a strip footing. Enter the footing size and the concrete footing calculator returns the total concrete in cubic metres and cubic yards, with an optional cost when you add your local concrete price.
Results
The Concrete Footing Calculator is part of our Concrete collection. Browse more concrete to size, convert, and check your work alongside this tool.
What the concrete footing calculator shows
Footings spread a building's weight into the ground. A strip footing runs continuously under a wall; pad footings sit under posts or columns. The concrete footing calculator works out the concrete for either type, adds a foundation wall on top of a strip footing if you have one, and applies a waste allowance so the order covers uneven trenches.
Calculate concrete for footing: the formulas
The total is multiplied by (1 + waste ÷ 100) and converted to cubic yards by multiplying cubic metres by 1.308.
Concrete footer estimator example
A 40 m strip footing, 0.6 m wide and 300 mm deep, with a 1 m high, 200 mm thick foundation wall and 5 percent waste:
At a concrete price of 150 per cubic metre, the concrete costs about 2,394.
How to use the footing calculator
Choose strip or pad footing. For a strip footing, enter the total run of the footing (for a rectangle, its perimeter), its width, and its depth, plus the foundation wall height and thickness if there is one. For pad footings, enter the length, width, depth, and the number of pads. Add a waste allowance and, optionally, your concrete price per cubic metre for a cost.
Reading the footing volume calculator result
Order ready-mix by the total volume, rounded up to the supplier's increment. Trenches are rarely perfectly square, so keep a 5 to 10 percent allowance. This tool finds the volume of footings whose size you already know; the size itself depends on soil strength and loads and should come from your plans or an engineer.
When figuring concrete footings
- Ordering ready-mix for a house or garage strip footing
- Pricing a job with the concrete footing cost calculator
- Planning pad footings for a deck or carport
- Checking a footing estimate from a contractor
Common concrete footing calculator mistakes
- Mixing millimetres and metres. Depth is entered in millimetres here.
- Counting corners twice. Use the centreline run around the building.
- No waste allowance. Trenches are rarely exact.
Tips for accurate results
- Measure trench depth at several points and average.
- Order a little extra rather than run short mid-pour.
- Confirm footing size with your plans.
Concrete slab and footing calculator: planning both pours
Many foundations combine a slab with thickened edge footings or separate strip footings. Calculate each part on its own: the footing here, and the slab with a slab calculator, then add them for the order. Footings usually need reinforcing bars along their length, and the rebar calculator counts the bars and their total length.
Footing calculator: strip vs pad footings
Strip footings carry walls along their whole length, so their volume grows with the perimeter. Pad footings carry concentrated loads from posts or columns, so their volume grows with the number of supports. A building can use both.
Footing calculator reference (strip footing, per 10 m run)
| Width | Depth | Concrete |
|---|---|---|
| 0.4 m | 200 mm | 0.8 m³ |
| 0.45 m | 250 mm | 1.13 m³ |
| 0.6 m | 300 mm | 1.8 m³ |
| 0.75 m | 400 mm | 3.0 m³ |
Before waste.
Concrete Footing Calculator FAQ
How do I calculate concrete for a footing?
Multiply length × width × depth in metres for cubic metres, then add 5 to 10 percent waste.
What length do I use for a strip footing?
The total run of the footing; for a simple rectangle, its perimeter.
Does this size the footing?
No. It finds the volume of a footing whose size you know; sizing depends on soil and loads.
How many cubic yards are in a cubic metre?
About 1.308.