How pool volume is calculated
Volume is surface area × average depth × 7.48, the number of gallons in a cubic foot. Average depth is the shallow end plus the deep end, divided by two. That's close enough for a pool with a steady slope. If most of the pool is shallow with a small deep well, weight the average toward the shallow depth.
| Shape | Formula (gallons) |
|---|---|
| Rectangle | length × width × avg depth × 7.48 |
| Round | diameter² × avg depth × 5.9 |
| Oval | length × width × avg depth × 5.9 |
| Kidney | (A + B) × length × 0.45 × avg depth × 7.48 |
Measuring a kidney pool
A is the width across the widest part of the larger lobe and B is the width across the smaller lobe. Length is the longest straight line end to end.
What to do with the number
Plug it into the pool chemical calculator to get exact doses. If you service the pool regularly, the most accurate check is to dose a known amount of salt or stabilizer and compare the before-and-after test readings.