FREE POOL PLANNING TOOL
Pool Volume Calculator
Estimate pool gallons from the water dimensions—not the shell or coping. The result gives you a consistent starting point for equipment discussions, operating plans, refill calculations, and proposal comparisons.
STEP 01
Enter the inside dimensions
Measure the water area—not the outside of the coping. Use the shallow and deep water depths, not the wall height.
ESTIMATED WATER VOLUME
18,193 gallons
Approximate volume for a rectangle or square pool with an average water depth of 4.75 ft.
- Approximate cubic feet
- 2,432
- Water weight
- 151,730 lb
- Flow for 8-hour turnover
- 38 GPM
- Flow for 6-hour turnover
- 51 GPM
HOW THE ESTIMATE WORKS
Shape, dimensions, and average water depth
Rectangular and round pools use standard geometric volume. Oval and kidney pools use established approximation factors because their curved outlines do not fill the complete bounding rectangle. Every result is converted using 7.48052 US gallons per cubic foot.
The largest avoidable error is usually depth. A pool described as “3½ to 8 feet” does not contain eight feet of water everywhere. The calculator averages the shallow and deep measurements. For a complex floor, calculate separate sections and add their gallons.
Measure the water line
Measure inside length and width at the normal operating water level. For freeform pools, take two representative widths instead of using the widest point twice.
Check the depth profile
Record water depth at the shallow and deep ends. Large shelves, benches, beach entries, spas, or surge tanks should be handled as separate volumes.
Use gallons as one input
Volume informs turnover, heating, filling, and chemical planning, but it does not determine equipment alone. Ask for hydraulic and electrical assumptions in writing.
USE IT WITH PROPOSALS
Questions the volume result should trigger
- What design volume does each Pool Builder use?
- What turnover assumption supports the proposed flow rate?
- Where is total dynamic head documented?
- Do pump, filter, heater, sanitizer, and feature requirements agree?
- How will the completed pool volume be confirmed for startup?
- Who provides the final equipment schedules and operating settings?
POOL VOLUME FAQ
Questions behind the number
How do I calculate the average depth of a pool?
Add the shallow water depth and deep water depth, then divide by two. That is a useful approximation for a pool with a reasonably even floor slope. Pools with shelves, multiple transitions, deep diving wells, or large benches need a more detailed section-by-section calculation.
Should I measure the pool wall or the water?
Use inside water dimensions and the normal operating water level. Coping width, wall thickness, and empty wall height are not part of the water volume. For an existing pool, measuring several widths and depths produces a better estimate than using one nominal size.
How accurate is a kidney-shaped pool estimate?
The kidney formula averages two widths and applies a standard shape factor. It is suitable for early planning, but it cannot perfectly represent every freeform curve, tanning ledge, bench, or attached spa. Divide a complex pool into simpler measured sections when accuracy matters.
Can I use estimated gallons to size a pump or filter?
Volume is one input, not the complete selection. Hydraulic resistance, pipe size, fittings, elevation, features, required turnover, local code, equipment curves, sanitation system, and operating strategy also matter. A qualified designer or installer should verify final equipment sizing.
Can I use this estimate for chemical dosing?
Use it as a starting estimate only. Verify the actual volume where possible, test the water, follow the product label, add chemicals conservatively, circulate, and retest. Never mix pool chemicals or rely on a calculator instead of label instructions.