Free estimate — verify against local code before building
Concrete Footing Calculator
Enter finished footing dimensions to compare ready-mix yards, bag counts, and optional cost.
What this calculator includes
Calculate the concrete inside rectangular continuous footings, grade beams, or repeated footing runs. Enter the finished footing dimensions and quantity, then compare ready-mix volume with common bag counts before requesting a supplier quote.
How to use this concrete footing calculator
- 01
Use the approved footing dimensions
Enter the finished concrete length, width, and depth from the project drawings—not the excavator bucket width.
- 02
Count repeated runs
Use quantity for identical footings; calculate different sizes separately and combine the ready-mix volumes.
- 03
Set a waste allowance
Account for uneven trenches, spillage, and form variation without changing the designed footing dimensions.
- 04
Choose the purchase path
Compare bagged mix with ready-mix, then confirm supplier minimums, delivery access, and order increments.
Worked example
Example: two 20 ft footing runs
Two footings, each 20 ft long × 24 in wide × 12 in deep, contain 80 ft³ or 2.96 yd³. With 10% waste, plan for 3.26 yd³ before supplier rounding.
Practical buying and overage guidance
Ask the ready-mix supplier about minimum loads, short-load fees, delivery window, truck access, and the increment used to round orders. For bags, verify yield on the exact product label.
Continue the project
Pour a Concrete Slab
Plan slab excavation, base, concrete yards or bags, forms, reinforcement allowances, delivery, labor, equipment, and contractor pricing.
Open the project workflow →Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- NRMCA — Concrete in Practice (opens in a new tab)
Concrete ordering and placement guidance.
- QUIKRETE Concrete Mix product data (opens in a new tab)
Planning yields for common bag sizes.
Frequently asked questions
What footing dimensions should I enter?
Use the finished concrete dimensions shown on the approved plan. The calculator does not choose footing width, depth, strength, or reinforcement.
How do I calculate several different footing sizes?
Run each size separately, add the unrounded cubic-yard volumes, then apply your supplier's order increment to the combined amount.
How much extra concrete should I order for footings?
Waste depends on whether the pour is formed or placed against earth and how uniform the excavation is. Use an allowance based on actual site conditions and supplier guidance.
Does the result include concrete for walls or piers?
No. It includes only the rectangular footing volume entered. Calculate walls, columns, keyways, and thickened areas separately.
Can this calculator size a foundation footing?
No. Footing sizing depends on loads, soil bearing, frost depth, reinforcement, and local code. Use approved plans or a qualified design professional.