Concrete & masonry
Footing Concrete Calculator
Estimate continuous footing concrete in ready-mix cubic yards or whole bags, with waste, order rounding and optional cost.
Estimated order quantity
0.00 yd³ ready-mix order
- Waste and order rounding
- Bag yield
- Excavation variation, stepped footings, piers, keyways and thickened areas must be measured separately.
Planning estimate only. Verify product specifications, site conditions, and supplier purchase increments before ordering.
How to calculate concrete for a continuous footing
Multiply total footing length by formed width and thickness, converting both inch dimensions to feet. Add the selected allowance, then round up to a ready-mix purchase increment or whole bags.
Concrete with waste: net volume × (1 + waste)
Ready-mix order: round up to the selected yd³ increment
Bags: round up(volume with waste ÷ published bag yield)
Worked example
A 40 ft continuous footing that is 16 inches wide and 8 inches thick contains 35.56 ft³, or 1.317 yd³. With 10% waste, the estimate is 1.449 yd³. Rounded to quarter-yard ordering, plan for 1.50 yd³; the 80 lb bag alternative is 66 whole bags.
Quantity is not footing design
This calculator estimates a specified geometry only. Footing width, thickness, depth, reinforcement and concrete properties depend on loads, soil bearing, frost, seismic and wind conditions, drainage, local code and approved plans. The 2024 IRC states that footing width is based on soil load-bearing value; use the locally adopted code and qualified design guidance.
Before ordering
- Use dimensions from approved plans; do not use this calculator to size a structural footing.
- Measure stepped sections, pads, piers, pilasters and grade beams separately and add their volumes.
- Confirm excavation condition, form dimensions, reinforcement, cover, utilities, inspection and placement access.
- Confirm mixture requirements, minimum load, short-load fees, delivery timing and order increments with the supplier.
Current US references: 2024 International Residential Code, Chapter 4, QUIKRETE mixing and yield guidance, and NRMCA/ASCC ready-mix ordering checklist. Local adopted code, plans, product data and supplier terms control.
Footing concrete calculator FAQ
How do I measure several footing runs?
Add the lengths using one consistent method. At corners and intersections, avoid counting overlapping concrete twice; complex layouts are best split into non-overlapping prisms.
Does this size the footing?
No. It calculates volume from dimensions already selected by approved plans or qualified guidance.
How much extra concrete should I order?
The visible 0%, 5%, 10% and 15% options let you reflect excavation and form uncertainty. Choose from field conditions and supplier guidance.
Why is the order larger than the volume?
The allowance is added first, then the result is rounded up to the selected commercial order increment.