How the d-shaped pool volume calculator works
Multiply the straight section length by the width, then add half of 3.1416 times half the width squared for the curved end.
Add the two areas and multiply by the average water depth. The curved end is often the shallow end.
The formula
Volume = (length x width + 3.1416 x (width / 2) squared / 2) x average depth
Measure: Straight length, width, average depth.
Worked example
A 20 foot straight section 14 feet wide is 280 square feet. The semicircle adds 77 square feet.
The 357 square foot total at 4.5 feet average depth is 1,606 cubic feet, near 12,017 gallons or 45,480 litres.
Tips before you measure
Measure the straight section only up to where the curve begins, or you will count the curve twice.
The width doubles as the diameter of the semicircle, so it needs to be accurate.
D-Shaped pool volume FAQs
Where does the straight section end?
At the point where the side wall stops running parallel and starts to curve inward.
Is this the same as a Roman end pool?
Close. A Roman end is usually a flatter curve, and a D-shape uses a full semicircle.
What if both ends curve?
Use the Roman calculator and set the number of rounded ends to 2.
Other pool shapes
Not quite the right outline? The main pool volume calculator covers all 20 shapes with the same units and formulas.