Concrete planning tool
Concrete Footing Calculator
Estimate the concrete volume for rectangular pad or continuous footings. Enter the dimensions you plan to use, the number of identical footings, and an optional waste allowance.
Footing dimensions
Enter the dimensions of each footing
Dimensions apply to each identical footing. Waste allowance is added to their combined concrete volume and shown separately.
Concrete required
Concrete volume for the specified footings
Concrete required
0.30yd³
- Volume per footing
- 8.00 ft³
- Before waste
- 8.00 ft³
- Waste allowance
- 0.00 ft³
- Including waste
- 8.00 ft³
Live diagram
Footing visualization
Diagram shows relative proportions, not scale.
How it works
From footing dimensions to concrete volume
The calculator finds the rectangular volume of each footing, multiplies it by the number of identical footings, and applies your selected waste allowance.
Rectangular footing formula
Multiply length by width by depth using compatible units. For multiple identical footings, multiply that volume by the footing count.
Volume per footing = length × width × depth
Total = volume per footing × quantity × (1 + waste percentage ÷ 100)
Worked example: four identical rectangular footings
This arithmetic example uses 4 ft × 2 ft × 1 ft dimensions and is not a recommended footing design.
- Volume per footing4 × 2 × 1 = 8 ft³
- Before waste8 × 4 = 32 ft³
- 10% waste32 × 10% = 3.2 ft³
- Total concrete35.2 ft³ ≈ 1.30 yd³
Multiple identical footings
Length, width, and depth apply to each footing. Quantity multiplies that individual volume. Calculate groups with different dimensions separately.
Using one continuous strip footing
For a uniform continuous footing, enter the total developed length, the uniform width and depth, and set Number of identical footings to 1. If the cross-section changes, calculate each uniform section separately.
Waste allowance
Waste is applied after calculating the combined base volume. Enter the allowance appropriate for your project; the calculator does not prescribe one.
Cubic feet, cubic yards, and cubic meters
US Customary results show the purchasing-oriented total in cubic yards with supporting cubic-foot values. Metric results use cubic meters. Unit switching preserves the same physical footing dimensions.
Estimate limitations
This calculator estimates rectangular footing concrete volume, assumes identical dimensions when quantity exceeds one, and assumes a uniform cross-section for continuous footing use. It does not determine footing dimensions, soil bearing capacity, structural loads, reinforcement, frost depth, code compliance, excavation safety, or engineering suitability.
Use project plans, local requirements, and qualified professional guidance where required.
Frequently asked questions
- How do I calculate concrete for a rectangular footing?
- Multiply length by width by depth, then multiply by the number of identical footings and add any selected waste allowance.
- Can I calculate several identical footings?
- Yes. Enter the dimensions of one footing and the number of identical footings.
- How do I use this calculator for a continuous footing?
- Enter the total developed length and uniform width and depth, then use a quantity of 1.
- Does this calculator determine the correct footing size?
- No. You supply the dimensions; the calculator estimates concrete volume only.
- Should I include a waste allowance?
- Enter the allowance that fits your project conditions. The calculator does not assume a universal percentage.
- Why is the result shown in cubic yards?
- Concrete volume is commonly estimated in cubic yards in US Customary workflows. Supporting cubic-foot values remain visible for auditing.
- Can it calculate concrete bags?
- Use the Concrete Bag Calculator with this volume and the product’s listed yield. V1 does not transfer values automatically.
- Does it account for rebar or column displacement?
- No. It calculates the full rectangular concrete volume and does not subtract reinforcement, columns, posts, or other displacement.