Pool Volume Calculator
Calculate how many gallons a rectangular, round or oval pool holds and the pump flow needed to turn that water over in 8 hours. Pool service pros need the number for chemical doses, and owners need it before the first fill or shock.
Free, no sign-up. Runs in your browser; nothing you type is stored unless you choose to email yourself the results.
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Three steps, about a minute
Step 1
Choose the Shape, then enter Length (or diameter) and Width (or diameter) in feet.
Step 2
Enter Shallow end depth and Deep end depth; use the same value for a flat-bottom pool.
Step 3
Read Pool volume in gallons and Turnover per 8 hours for pump and filter sizing.
How the pool volume calculator works
Volume is length × width × average depth × a shape factor, and average depth is shallow end plus deep end ÷ 2. Rectangles use 7.48, the number of gallons in a cubic foot. Round and oval pools use 5.9, which is roughly 7.48 × 0.785, the share of a rectangle that a circle or oval fills. For a 32 × 16 ft rectangle running from 3.5 to 8 ft deep, the average depth is 5.75 ft and the volume is about 22,021 gallons. Turnover divides gallons by 480 minutes, so that pool needs about 46 gallons per minute to cycle all of its water in 8 hours. The average-depth method assumes an even slope. A steep hopper, wide sun shelf or freeform shape can throw it off, and a water meter reading during a fill gives the true number.
| Shape | Rectangle |
|---|---|
| Length (or diameter) | 32 ft |
| Width (or diameter) | 16 ft |
| Shallow end depth | 3.5 ft |
| Deep end depth | 8 ft |
| Pool volume | 22,021 gallons |
|---|---|
| Average depth | 5.8 ft |
| Turnover per 8 hours | 46 gal/min |
Length × width × average depth × 7.48 for rectangles, × 5.9 for round and oval pools.
Using the numbers like a pro: tips for pool companies
Put each pool's gallons on the service record. Chemical doses are figured per gallon, and techs who guess at volume either waste product or leave the water out of balance.
Check that the pump and filter can handle the turnover flow before recommending equipment. A pump that is too small leaves water poorly circulated, and one that is too big wastes energy.
Use volume to tier pricing for openings, closings and green-to-clean jobs. Bigger pools take more chemicals and time, so volume tiers keep quotes fair across small and large pools.
Put a calculator like this on your own website
Pool owners look up their gallons when they're dosing chemicals or shopping for service. A volume calculator on your site meets them right there, then offers a weekly service quote or a water test. Ask for pool size and address in the form so you can see if they fit an existing route. We'll match the form fields to how your routes are organized.
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Pool Volume Calculator questions
How many gallons are in my pool?
Multiply length × width × average depth in feet, then multiply by 7.48 for a rectangle or 5.9 for a round or oval pool. A 32 by 16 ft pool averaging 5.75 ft deep holds about 22,021 gallons. A round pool 24 ft across and averaging 4 ft deep holds about 13,594 gallons.
What is pool turnover rate?
Turnover is the time it takes the pump to move the full volume of water through the filter once. Pools are commonly planned around at least one full turnover a day, and this calculator uses 8 hours. Divide gallons by 480 to get the gallons per minute an 8-hour turnover needs.
Why does pool volume matter for chemicals?
Chlorine, pH adjusters, alkalinity increaser and shock are all dosed by the amount of water. Guess low and the treatment won't hold. Guess high and you waste product and can push levels out of range. Knowing the gallons makes every dose more accurate and every visit faster.
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