Concrete Footing Calculator
Footing concrete is length × width × thickness — the full centreline run for a strip footing, or one side × the number of pads. A 60 ft strip footing 16 in wide and 8 in thick needs 1.98 yd³, or 2.18 yd³ with 10% waste. For slabs use the Concrete Calculator; for walls, the Wall Concrete Calculator.
How it's calculated: Volume = length × width × thickness (× number of pads for pad footings).
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
V = Length × Width × Thickness (× number of pads)
Run the calculation to see each step with your own numbers.
A strip footing 60 ft long, 16 in wide, 8 in thick, 10% waste.
V = 60 × 1.333 × 0.667 = 53.3 ft³ = 1.98 yd³ exact
+10%: order 2.18 yd³
- Rectangular cross-section of constant width and thickness.
- For a strip footing, 'length' is the total centreline run — subtract nothing for corners (a small over-count that the waste allowance absorbs).
- Keyways, steps in the footing, and the wall/pier above are not included.
- Strip vs pad footing?
- A strip footing runs continuously under a wall. A pad footing is an isolated block under a single column or post. Pick the type and the calculator handles the count.
- Do I subtract the corners on a strip footing?
- No. Entering the total centreline length slightly over-counts where footings overlap at each corner, and the waste allowance absorbs that — it keeps you from ordering short.
- Why add 10% when the trench is a fixed size?
- Footing trenches are rarely cut to an exact size — soil sloughs in and the pour overfills the loose edges. Raise the allowance above 10% if you are digging in loose, sandy or crumbling ground.
- How much concrete do I need for a footing?
- Multiply the footing length by its width and thickness in feet, then divide by 27 for cubic yards. A 60 ft × 16 in × 8 in strip footing is 53.3 ft³, or 1.98 yd³ before the 10% waste allowance.
- How much concrete per foot of a 16 × 8 inch footing?
- Each linear foot of a 16 in wide, 8 in thick footing holds about 0.89 ft³ (0.033 yd³), so roughly 30 ft of footing takes one cubic yard before waste.
Geometry
Standard geometry. Unit conversions per NIST SP 811.
About the Concrete Footing Calculator
The Concrete Footing Calculator works out the concrete for the spread footings that carry a wall or a column down to bearing soil — a continuous strip footing under a wall, or isolated pad footings under posts and columns. Enter the footing length (the full centreline run for a strip, or one side for a pad), its width and thickness, and for pads how many. The wall or pier that sits on top, and any reinforcing steel, are separate calculations.
What you enter
- Footing type
- Length — Total run for a strip footing; one side for a pad.
- Width
- Thickness
- Number of pads
- Waste allowance — Default 10%. Adjust to your own allowance — the exact figure is always shown too.
What you get back
- Concrete volume — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Concrete Calculator — How much concrete a rectangular slab or footing needs, in cubic yards or cubic metres.
- Wall Concrete Calculator — Concrete volume for a poured foundation or retaining wall.
- Concrete Pier Calculator — Concrete volume for pier foundations with an optional bell base.
- Concrete Column Calculator — Concrete volume for round or square columns.
- Rebar Calculator — Rebar quantity, spacing and lineal feet for a slab or footing grid.
Related articles
- Exact Quantity vs Recommended Order Quantity — Every BuildNumerics calculator shows two figures on purpose — the exact geometric answer, and a separate, waste-adjusted number you can actually order.
Part of the Concrete calculators.