How the roman pool volume calculator works
Work out the rectangle area first, then add a half ellipse for each rounded end. Each end area is 3.1416 times half the width times the extension, divided by two.
Add the areas together and multiply by average depth. Choose one or two rounded ends depending on your build.
The formula
Volume = (rectangle area + curved end area) x average depth
Measure: Rectangle length and width, end extension, average depth.
Worked example
A 28 by 16 foot rectangle is 448 square feet. Two ends extending 3 feet each add about 37.7 square feet each.
The 523 square foot total at 5 feet average depth is 2,616 cubic feet, near 19,570 gallons or 74,070 litres.
Tips before you measure
Measure the end extension from the last straight point of the wall to the furthest point of the curve.
Roman ends are often the shallow end. Take your shallow depth reading inside the curve, not at the step.
Roman pool volume FAQs
What is a Roman end pool?
A rectangular pool with a semicircular or rounded end on one or both short sides, often with steps set into the curve.
Do steps change the volume?
Yes, slightly. Steps displace water, so a stepped Roman end holds a few hundred gallons less than the formula shows.
Can I have just one rounded end?
Yes. Set the number of rounded ends to 1 and the calculator adds a single half ellipse.
Other pool shapes
Not quite the right outline? The main pool volume calculator covers all 20 shapes with the same units and formulas.