Hot Tub Volume Calculator
Estimate hot tub volume from entered measurements.
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What this tool does
Estimate hot tub volume from entered measurements. Use actual water depth, not wall height. Kidney shapes are a rough 0.75 area approximation; irregular pools should be measured in sections.
How to use the Hot Tub Volume Calculator
- Enter or select pool shape.
- Enter or select main length in ft.
- Enter or select main width in ft.
- Enter or select average water depth in ft.
- Enter or select l-shape extension length in ft.
- Enter or select l-shape extension width in ft.
- Read the calculated result; change any measurement to compare alternatives.
Formula
rectangle area=L×W; oval=πLW/4; kidney≈0.75LW; L-shape=main rectangle+extension; gallons=area×average depth×7.48052
- shape
- Pool shape
- length
- Main length (ft, before metric conversion)
- width
- Main width (ft, before metric conversion)
- depth
- Average water depth (ft, before metric conversion)
- extraLength
- L-shape extension length (ft, before metric conversion)
- extraWidth
- L-shape extension width (ft, before metric conversion)
Use actual water depth, not wall height. Kidney shapes are a rough 0.75 area approximation; irregular pools should be measured in sections.
Worked example
For hot tub volume calculator, the following measurements illustrate the exact method: Pool shape: rectangle; Main length: 30; Main width: 15; Average water depth: 4.5; L-shape extension length: 10; L-shape extension width: 8.
Inputs
- Pool shapeRectangle
- Main length30 ft
- Main width15 ft
- Average water depth4.5 ft
- L-shape extension length10 ft
- L-shape extension width8 ft
Result
- Estimated water volume15,148.05 gal
- Water volume (liters)57,341.61
Results explained
- Estimated water volume
- Estimated water volume from the formula above, expressed in gal before metric conversion. Use actual water depth, not wall height. Kidney shapes are a rough 0.75 area approximation; irregular pools should be measured in sections.
- Water volume (liters)
- Water volume (liters) from the formula above. Use actual water depth, not wall height. Kidney shapes are a rough 0.75 area approximation; irregular pools should be measured in sections.
Frequently asked questions
rectangle area=L×W; oval=πLW/4; kidney≈0.75LW; L-shape=main rectangle+extension; gallons=area×average depth×7.48052
Use actual water depth, not wall height. Kidney shapes are a rough 0.75 area approximation; irregular pools should be measured in sections.
Verify dimensions, product concentration and equipment instructions. Use a qualified pool professional for final chemical dosing and equipment sizing.
No. The entered figures are processed only in your browser.
Follow each input's unit label. Imperial and metric switching converts the labelled geometry and volume measurements.