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Estimate concrete for solid circular cylinders such as columns, piers, bollard bases and round footings. Calculate repeated cylinders, waste allowance, weight, bag count and supplier cost.
Cylinder formula
Every dimension is converted to feet before the formula is applied. The result is also shown in cubic yards and cubic meters.
Worked example
Four cylinders, each 2 ft in diameter and 8 ft high, contain 100.53 ft³. Adding 10% gives 110.58 ft³, or about 4.096 yd³.
Visual guide
Measure formwork inside dimensions. For hollow pipes or annular shapes, subtract the inner-cylinder volume from the outer-cylinder volume.
Field checklist
- Confirm whether drawings specify diameter or radius.
- Measure drilled holes after cleaning and before placement.
- Allow for irregular soil, over-excavation and form leakage.
- Calculate enlarged bases or caps as separate shapes.
- Check cage clearance, anchor bolts and embedments.
- Confirm truck minimums, short-load fees and access.
Bag yield varies by product and bag size. Use the manufacturer value printed on the package.
Frequently asked questions
Can this calculate post holes?
Yes, when the hole is approximately cylindrical. Irregular holes need a larger allowance.
Is diameter the same as radius?
No. Radius is half the diameter, and using diameter as radius makes the volume four times too large.
Does the result include waste?
The net volume excludes waste; the adjusted order volume includes your selected allowance.
Can I use metric measurements?
Yes. Select meters or centimeters and all results are converted automatically.
Common mistakes
- Entering radius in the diameter field.
- Mixing inches and feet.
- Forgetting the number of cylinders.
- Ignoring bell bottoms or irregular excavation.