How the lap pool volume calculator works
Multiply length by width for the surface area, then by average water depth. Most lap pools have a flat floor, so one depth reading is usually enough.
Cubic feet times 7.48 gives US gallons. The results panel also shows litres and cubic metres.
The formula
Volume = length x width x average depth
Measure: Length, width, average depth.
Worked example
A 45 by 8 foot lap pool covers 360 square feet. At 4 feet deep that is 1,440 cubic feet.
That is close to 10,772 gallons, or 40,770 litres.
Tips before you measure
High surface area means high evaporation. A cover pays for itself faster on a lap pool than on any other shape.
Long runs need good circulation. Check the turnover rate once you know the volume.
Lap Pool pool volume FAQs
How many gallons is a 40 foot lap pool?
At 8 feet wide and 4 feet deep a 40 foot lap pool holds around 9,575 gallons.
Does length hurt circulation?
It can. Narrow pools often need a return at the far end so the water at the ends does not stagnate.
Is a swim spa the same?
No. Swim spas are shorter and deeper, so use the hot tub calculator instead.
Other pool shapes
Not quite the right outline? The main pool volume calculator covers all 20 shapes with the same units and formulas.