Concrete Footing Calculator
Calculate cubic yards of concrete for continuous or isolated rectangular footings, including quantity and waste.
What this result actually means
Footing quantity gets distorted quickly when width, thickness, or the number of isolated pads changes. This page separates the geometric volume from the overage you choose to order, so the waste allowance never hides inside the base math.
Use dimensions from the actual footing schedule or field measurements. The calculator does not choose a structural footing size; it only converts the dimensions you enter into cubic feet and cubic yards.
Inputs that control the answer
Material quantity pages are most useful when they separate geometry, unit conversion, and purchasing allowance. The math can be exact from the inputs while the jobsite assumptions remain estimates.
| Input | Example | What to enter |
|---|---|---|
| Footing length (ft) | 40 | Measure or source this value from the real job, route, or record. Unit mistakes here propagate directly into the result. |
| Footing width (ft) | 2 | Measure or source this value from the real job, route, or record. Unit mistakes here propagate directly into the result. |
| Footing thickness (in) | 12 | Measure or source this value from the real job, route, or record. Unit mistakes here propagate directly into the result. |
| Number of footings | 1 | Enter the count that belongs to the same scenario as the other inputs; avoid mixing totals from different periods or project sections. |
| Waste / overage (%) | 8 | A separate buffer for cuts, handling, uncertainty, laps, spill, or touch-up. Keep it visible instead of burying it in the base measurement. |
Worked example
Using the example values loaded in the calculator (Footing length (ft) = 40, Footing width (ft) = 2, Footing thickness (in) = 12, Number of footings = 1, Waste / overage (%) = 8), the browser-side formula produces the outputs below. These are example numbers, not recommended project or business settings.
| Output | Example result |
|---|---|
| Base volume (yd³) | 2.96 |
| Order volume with waste (yd³) | 3.2 |
| Volume (ft³) | 80 |
First checkpoint: Base volume (yd³) = 2.96. Change the inputs to your real scenario before using the number for an order, budget, quote, bid, reimbursement, or operating decision.
Test the assumption before you trust the total
Footing quantity gets distorted quickly when width, thickness, or the number of isolated pads changes. This page separates the geometric volume from the overage you choose to order, so the waste allowance never hides inside the base math.
Use the example buttons above to move several inputs together, then change one field at a time. That makes sensitivity visible: you can tell whether the result is mostly driven by size, rate, coverage, waste, quantity, or another assumption.
Where estimates go wrong
- Do not substitute this volume estimate for structural design or code requirements.
- Keep all footing lengths and quantities separate when different sections use different dimensions.
- Ready-mix order increments, short-load charges, pump waste, and site access can affect the quantity you actually purchase.
Use dimensions from the actual footing schedule or field measurements. The calculator does not choose a structural footing size; it only converts the dimensions you enter into cubic feet and cubic yards.
Related calculators
Questions people run into
Does this calculator choose the correct construction specification?
No. It converts the dimensions, spacing, density, or allowance you enter into a quantity. Structural dimensions, layer thickness, reinforcement, and material specifications must come from the project requirements that apply to the work.
Why might the delivered quantity differ from the calculation?
Field dimensions, subgrade variation, compaction, form leakage, supplier density, order increments, and handling losses can all move the real purchase away from a clean geometric estimate.
Should I round the answer?
Keep the raw result for comparison, then round only according to how the material is actually sold or delivered. Whole bags, whole bars, truck increments, and minimum orders can matter more than extra decimal places.
Method and limits
Formula: Cubic yards = length × width × thickness ÷ 12 ÷ 27 × quantity × (1 + waste %).
The calculator runs locally in your browser from the values you enter. The mathematical result is deterministic from those inputs; the planning accuracy depends on whether the inputs represent the real job, route, policy, product, or operating conditions. When the result is close to a purchase threshold, package boundary, safety limit, or financial break-even point, verify the controlling assumption before acting.
Reviewed for calculator depth and clarity · September 2026 · Methodology