Get the volume of a round footing.
⚙️Calculation Parameters
📊Calculated Output
How Round Footing Volume Calculator Works?
To size a round footing, the Round Footing Volume Calculator treats the pad as a short, wide cylinder and multiplies its area by its thickness. The process takes 4 steps.
Enter the footing diameter
Type the width of the round pad, often 16 in to 36 in (41 cm to 91 cm).
Enter the thickness
Type the pad depth. Many residential pads are 8 in to 12 in (20 cm to 30 cm) thick.
Calculate the volume
The calculator applies V = π × r² × t and shows cubic feet (ft³), cubic yards (yd³) and bags.
Check bearing area
The tool shows the base area in square feet (ft²) for a soil pressure check.
Round Footing Volume Calculator Formula
The Round Footing Volume Calculator uses a cylinder with a small height.
Footing volume
V = π × (D ÷ 24)² × (t ÷ 12)D is footing diameter and t is thickness, in inches.
Bearing area
A = π × (D ÷ 24)²Square feet of soil contact.
Soil pressure
q = P ÷ AP is the load in pounds (lb); compare q with allowable soil pressure.
Worked example: 24 in × 8 in round pad
- A = 3.1416 × 1² = 3.14 ft²
- V = 3.14 × (8 ÷ 12) = 2.094 ft³ (59 L)
- Bags = ⌈2.094 ÷ 0.60⌉ = 4 bags of 80 lb
Round Footing Volume Calculator Conversion Table
The round footing conversion table lists 6 pad sizes with volume, 80 lb (36 kg) bags and bearing area.
| Footing | Metric size | ft³ | yd³ | 80 lb bags | Bearing ft² |
|---|---|---|---|---|---|
| 16 in × 8 in | 41 cm × 20 cm | 0.93 | 0.034 | 2 | 1.40 |
| 20 in × 8 in | 51 cm × 20 cm | 1.45 | 0.054 | 3 | 2.18 |
| 24 in × 8 in | 61 cm × 20 cm | 2.09 | 0.078 | 4 | 3.14 |
| 24 in × 10 in | 61 cm × 25 cm | 2.62 | 0.097 | 5 | 3.14 |
| 30 in × 10 in | 76 cm × 25 cm | 4.09 | 0.152 | 7 | 4.91 |
| 36 in × 12 in | 91 cm × 30 cm | 7.07 | 0.262 | 12 | 7.07 |
Footing size depends on load and soil. Follow the project design or local code.
What is Round Footing Volume Calculator?
A Round Footing Volume Calculator is a concrete calculator for circular footing pads, the wide bases poured under piers and columns.
A round pad spreads a column load over more soil. A 24 in pad covers 3.14 ft², 4 times the 0.79 ft² base of a 12 in tube. The calculator sizes the concrete for that pad and reports the bearing area at the same time.
Round pads are poured in an augered or dug round hole, or inside a short wide form cut from a large tube.
What are the uses of Round Footing Volume Calculator?
There are 4 main uses of the Round Footing Volume Calculator.
Pier bases
Builders pour a round pad under each deck or porch pier.
Column footings
Contractors size pads under round steel or wood columns.
Augered pads
Crews fill the flat bottom of a wide auger hole.
Bearing checks
Designers compare pad area with soil capacity.
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