Concrete Footing Calculator
Turn footing geometry into cubic yards and whole concrete bags without guessing structural dimensions.
- Footing shape
- Rectangular / strip footing
- Volume before allowance
- 40 ft³ (1.48 yd³)
- Order volume
- 44 ft³ (1.63 yd³)
- Whole bags
- 74
Enter dimensions from an approved footing design. This calculator does not choose width, depth, reinforcement, bearing, frost depth, or load capacity.
Show calculation
ceil(20 ft³ × 2 × 1.1 ÷ 0.6 ft³/bag) = 74 bagsTransparent method and editable product assumptions. Verify current labels and project requirements.
How this calculator works
Rectangular mode multiplies strip length by width and depth. Round mode treats the entered width as a circular diameter and ignores rectangular length.
Volume is multiplied by the number of matching footings and a placement allowance. Whole bags are rounded only after the selected product’s finished yield is applied.
Footing dimensions must come from an approved design that accounts for soil, loads, frost, reinforcement and code.
Formula
Rectangular volume = L × W × D; round volume = π(D/2)² × depth; bags = ceil(order volume ÷ bag yield)The live result uses the selected cross-section.Control example: two strip footings
Each footing is 10 ft long, 24 in wide and 12 in deep, for 20 ft³ each.
Two footings with 10% allowance need 44 ft³. At 0.60 ft³ per bag: ceil(73.33) = 74 bags.
Assumptions and limits
- Enter dimensions from the plans and the approximate finished yield printed for the exact concrete mix and bag size.
- Measurements describe one simple project geometry.
- Waste and package values are editable planning assumptions.
- It does not select footing size, depth, reinforcement, soil bearing, frost protection, anchor details, or structural capacity.
Common measuring mistakes
- Mixing nominal dimensions with actual installed coverage.
- Skipping whole-package or stock-length rounding.
- Failing to verify the page’s stated measurement and product assumptions.
- Using a planning estimate outside the limitations stated on this page.
Sources
Product-specific values remain editable. These sources support the method and stated examples; they are not a universal substitute for your supplier’s current label.
- QUIKRETE Concrete Mix data sheet Publishes approximate finished yields by bag size.
- QUIKRETE deck footing guide Shows concrete placement in footing forms while leaving structural dimensions to the project.
Questions people ask
What does the Concrete Footing Calculator calculate?
Calculate concrete footing volume and whole bags for rectangular strip footings or round pier footings from approved dimensions.
How does this concrete footing calculator work?
Rectangular volume = L × W × D; round volume = π(D/2)² × depth; bags = ceil(order volume ÷ bag yield)
Which measurements should I enter?
Enter dimensions from the plans and the approximate finished yield printed for the exact concrete mix and bag size.
Does the estimate include every project requirement?
No. It does not select footing size, depth, reinforcement, soil bearing, frost protection, anchor details, or structural capacity.
Can I use metric measurements?
Yes. Switch to Metric above the form. The calculator converts the displayed measurements while keeping the same geometry and whole-item rounding.