Formula used
How to use this calculator
Select the calculation mode matching your known measurements. Enter values, choose units, and set quantity. The calculator converts every measurement before applying the selected formula.
- Choose a direct or reverse calculation mode.
- Enter the requested circle measurement and depth.
- Select units independently for each measurement.
- Add quantity and optional waste allowance.
- Choose decimal precision and calculate.
- Review results, conversions, and calculation steps.
Example data
| Diameter | Depth | Quantity | Volume |
|---|---|---|---|
| 6 ft | 1 ft | 1 | 28.274 ft³ |
| 4 ft | 2 ft | 1 | 25.133 ft³ |
| 3 ft | 1.5 ft | 4 | 42.412 ft³ |
Common applications
Use this tool for round slabs, holes, tanks, wells, planters, pools, and footings. It also estimates soil, gravel, concrete, mulch, water, or excavation volume. Always confirm field dimensions before purchasing materials or scheduling delivery.
Frequently asked questions
Can a circle have cubic feet?
A flat circle has square feet, not cubic feet. Adding depth creates a cylindrical three-dimensional space. That space can then be measured in cubic feet.
What formula calculates cubic feet for a circle?
Multiply π by the radius squared and depth. Keep every dimension in feet before calculating. The resulting unit is cubic feet.
Can I enter diameter instead of radius?
Yes, select the diameter and depth mode. The calculator divides diameter by two automatically. It then calculates area and volume.
Can depth use a different unit?
Yes, every measurement has an independent unit selector. Diameter can use feet while depth uses inches. Internal conversion keeps the calculation consistent.
Does the calculator accept fractions?
Yes, enter values such as 1/2 or 3 1/2. Mixed fractions are converted into decimals automatically. Invalid fractions produce a clear validation message.
How does waste allowance work?
The calculator first totals all identical sections. It then adds the selected waste percentage. This helps cover spillage, compaction, and measurement variation.
Can I calculate required depth?
Yes, choose a required-volume-to-depth mode. Enter the target volume and circle measurement. The calculator divides per-item volume by circular area.
Can I calculate the required radius?
Yes, choose required volume and depth to radius. The calculator determines area before solving radius. Diameter and circumference are also displayed.
Why is my result extremely large?
A mismatched unit often causes an oversized result. Check diameter, depth, and volume unit selections carefully. The calculator warns when dimensions appear unusually large.
Can I convert the answer to gallons?
Yes, the result table includes US and Imperial gallons. It also includes litres and metric cubic units. Conversion values use the adjusted final volume.
How accurate is the calculator?
Accuracy depends on measurements, units, and chosen precision. Standard π provides sufficient accuracy for most projects. Field conditions may still require practical allowances.