Concrete Footing Calculator
Estimate strip-footing concrete volume and optional cost in Imperial or Metric units.
Use this concrete footing calculator to estimate ready-mix volume for continuous strip footings under foundations, retaining walls, garages, sheds and similar structures. Choose Imperial or Metric units, enter the footing dimensions and quantity, then add waste and an optional local price per cubic yard or cubic meter.
Your Estimate
Total Cubic Feet
35.56 cu ft
Total Cubic Yards
1.32 cu yd
Waste-Adjusted Cubic Yards (10%)
1.45 cu yd
Width and depth are converted from inches to feet before volume is calculated. Footing dimensions must follow approved plans, engineering requirements, soil conditions, frost depth and local code.
Results Actions
Common Strip Footing Planning Sizes
These ranges are general examples, not design recommendations. Required footing width, depth, reinforcement and frost protection depend on loads, soil, wall construction, climate and local code.
How to Use the Concrete Footing Calculator
- 1Choose Imperial or Metric units; switching modes loads sensible native defaults.
- 2Enter footing length in feet or meters.
- 3Enter footing width and concrete depth in inches or millimeters.
- 4Enter the number of identical footings.
- 5Choose a 5%, 10% or 15% waste allowance.
- 6Optionally enter the delivered concrete price per cubic yard or cubic meter.
- 7Review Imperial cubic feet and yards or Metric cubic meters, the waste-adjusted order volume and optional cost.
Concrete Footing Volume Formulas
- 1Convert footing width to feet by dividing inches by 12.
- 2Convert footing depth to feet by dividing inches by 12.
- 3Total cubic feet = footing length × width in feet × depth in feet × number of identical footings.
- 4Total cubic yards = total cubic feet ÷ 27.
- 5Waste-adjusted cubic yards = total cubic yards × (1 + waste percentage).
- 6Estimated concrete cost = waste-adjusted cubic yards × price per cubic yard when a price is entered.
- 7Metric width and depth in meters = millimeters ÷ 1000.
- 8Metric cubic meters = length in meters × width in meters × depth in meters × number of footings.
- 9Metric waste-adjusted volume = cubic meters × (1 + waste percentage).
- 10Metric estimated cost = waste-adjusted cubic meters × price per cubic meter when a price is entered.
Example Calculation
Imperial example: one footing 40 ft long, 16 in wide and 8 in deep has about 35.56 cu ft or 1.32 cu yd before waste and 1.45 cu yd with 10% waste. At $175 per cubic yard, estimated concrete cost is about $253.50. Metric example: one footing 12 m long, 450 mm wide and 200 mm deep has 12 × 0.45 × 0.20 = 1.08 m³ before waste and 1.19 m³ with 10% waste. At $220 per cubic meter, estimated cost is $261.36. Supplier ordering increments and minimum-load charges may require a larger order.
Accuracy & Assumptions
- Results are material-planning estimates only and do not determine structural footing size.
- The calculator assumes each footing is a straight rectangular prism with uniform width and depth.
- Imperial width and depth are converted from inches to feet; Metric width and depth are converted from millimeters to meters.
- All identical footings are assumed to have the same dimensions.
- Waste is applied to calculated cubic yards or cubic meters after all footing volumes are combined.
- The cost estimate covers concrete volume only and excludes delivery, short-load charges, pumping, labor, forms, excavation, gravel and reinforcement.
- Excavation irregularities, overdig, soft subgrade and concrete left in equipment can increase actual usage.
- Footing dimensions, bearing capacity, frost depth and reinforcement must be confirmed from approved plans, local code or a qualified professional.
Frequently Asked Questions
How do I calculate concrete for a strip footing?
Multiply footing length by width, depth and footing count using consistent units. Imperial mode converts cubic feet to cubic yards; Metric mode calculates cubic meters directly.
Why are width and depth entered in inches or millimeters?
Footing cross-sections are commonly shown in smaller units while footing runs use feet or meters. The calculator converts the cross-section to feet or meters before calculating volume.
How much extra concrete should I order for footings?
A 5% allowance may suit accurate forms and stable excavation, 10% is a common planning buffer, and 15% may be appropriate for irregular trenches or uncertain site conditions. Confirm the final order with your contractor or supplier.
What size should my concrete footing be?
This calculator does not design footings. Required width, depth and reinforcement depend on building loads, soil bearing capacity, frost depth, wall construction and local code. Use approved plans or consult a qualified professional.
Does this calculator include rebar?
No. It estimates concrete volume only. Use the Rebar Calculator for a preliminary reinforcement quantity, then follow the reinforcement shown on approved plans.
Does the cost include delivery and labor?
No. Optional cost is waste-adjusted cubic yards or cubic meters multiplied by the entered unit price. Delivery, short-load fees, pumping, labor, excavation, forms and reinforcement are separate.
Can I use this for retaining-wall footings?
Yes, for estimating concrete in a straight rectangular strip footing. The wall and footing still require a design appropriate for retained soil height, drainage, surcharge loads, soil and local requirements.
Can I use this calculator for stepped footings?
Calculate each segment with a different width, depth or elevation separately, then add the waste-adjusted volumes. A single entry assumes a uniform rectangular footing.
This calculator provides an Imperial or Metric concrete quantity estimate only and does not design a structural footing. Required footing width, depth, reinforcement, concrete strength, bearing capacity and frost protection vary by approved plans, engineering requirements, structural loads, soil conditions, frost depth, climate and local code. Confirm dimensions and reinforcement with a licensed professional or the local building department before excavation or placement.