Pool Water Volume Calculator
A 16×32 ft pool at 5 ft average depth holds about 19,200 gallons — enter your pool’s shape and dimensions and this pool water volume calculator returns gallons, a chlorine starting dose, and fill time.
Average depth = (shallow end + deep end) ÷ 2. Chlorine figure is a 3 ppm starter dose with 65% calcium hypochlorite — test and adjust.
Estimates only. Figures are planning ballparks based on national averages — actual prices vary by region, contractor, and project details. Get 2–3 local quotes before budgeting.
How the pool water volume calculator works
Every pool volume starts from cubic feet — length times width times average depth — then converts at 7.5 gallons per cubic foot. Oval pools use a 5.9 multiplier instead because the curved ends hold less water than the bounding rectangle.
The chlorine row converts volume to a starting dose: about 0.6 oz of 65% calcium hypochlorite per 1,000 gallons raises free chlorine by roughly 3 ppm. Fill time is simply volume divided by your hose flow rate.
gal = L × W × D × 7.5 (rect) · × 5.9 (oval) · chlorine oz = gal × 0.0006 · fill hrs = gal ÷ (gpm × 60)
Related tools
Keep exploring: Pool Square Footage Calculator for the surface area (liners and covers), plus Concrete Slab Calculator for the pool deck.
Pool water volume calculator FAQ
How do you calculate pool water volume in gallons?
Rectangle: length × width × average depth × 7.5. Oval: length × width × average depth × 5.9. Round: 3.14 × radius² × average depth × 7.5.
How do I find my pool’s average depth?
Add the shallow-end depth and the deep-end depth, then divide by 2. A 3 ft shallow end and 8 ft deep end averages 5.5 ft.
How much chlorine does a 20,000 gallon pool need?
About 12 oz of 65% calcium hypochlorite for a 3 ppm starter dose. Always test after dosing — the calculator above shows the exact figure for your volume.
How long does it take to fill a pool with a hose?
A 19,200-gallon pool at 9 gallons per minute takes about 35 hours. The calculator estimates fill time from your hose flow rate.
Does pool shape change the volume formula?
Yes — ovals use a 5.9 multiplier instead of 7.5 because the curved ends hold less water than a rectangle of the same length and width.
Is the volume the same for a saltwater pool?
Yes — volume math is identical. A salt system just generates the chlorine on site instead of you adding it manually.
How often should I test my pool water?
Two to three times per week for chlorine and pH during swim season; weekly for alkalinity, calcium, and stabilizer.