Cylindrical footing volume
π × (diameter ÷ 2)² × depth × number of footingsThe diameter and depth are converted to feet first. Because diameter is squared, a small measuring or drilling difference can noticeably change volume.
Concrete footing calculator
Calculate concrete for solid cylindrical footings, piers, columns, or tube forms using diameter, depth, and count.
Enter footing dimensions
Measure the finished cylindrical space the concrete will fill.
Volume does not establish a safe footing size
The cylinder calculation is suitable for material quantity after diameter, depth, and count have been selected. Soil bearing, frost, uplift, eccentric loading, reinforcement, and connections require an approved design or qualified evaluation.
- Use the actual excavation or form diameter.
- Exclude gravel or void space from concrete depth.
- Calculate bell bottoms, pads, and grade beams as separate shapes.
Check every hole or form
Measure the actual inside diameter of a tube form. For excavated holes, check the widest and narrowest points and more than one depth. Calculate groups separately when sizes differ.
This solid-cylinder page does not subtract a post; use the post-hole calculator when concrete surrounds a post.
Worked example
Six 18 in diameter × 3 ft deep footings
Radius18 in ÷ 12 ÷ 2 = 0.75 ft
Measuredπ × 0.75² × 3 × 6 = 31.81 ft³
With 10% waste31.81 × 1.10 = 34.99 ft³
Ready-mix34.99 ÷ 27 = 1.30 yd³
Assumptions and limitations
- Each footing is a straight, solid cylinder of equal size.
- Bell bottoms, pads, grade beams, embedded posts, and voids are not included.
- Soil collapse and rough excavation can increase actual volume.
- The calculator does not select footing dimensions or bearing capacity.
Design comes first
Footing size, depth, reinforcement, frost protection, and concrete strength depend on loads, soil, plans, and local requirements. Obtain an appropriate design before using this quantity estimate.