Pool Flow Rate Calculator
Pool water flow rate is important for determining the turnover rate and ensuring the pool water receives adequate filtration. Not cycling enough water through the filter can result in swimming pool algae blooms, cloudy pool water, and water balance issues.
Determine the flow rate needed to achieve your desired pool turnover rate.
How Many Gallons of Water Are in My Pool?
To determine how long your pool pump should run, you first need to know the volume of water in your pool. Use one of these simple calculations below to find your pool’s volume. By using these formulas, you can accurately estimate the volume of your pool to help determine the appropriate pump running time.
Rectangular Pool
Right Triangle Pool
Circular Pool
Oval Pool
Kidney Pool
Square and Rectangle Pools
Single Depth Formula
Length x Width x Depth x 7.5 = Approximate Volume (Gallons)
Variable Depths Formula
Length x Width x Average Depth x 7.5 = Approximate Volume (Gallons)
Average Depth Calculation: If the pool has a shallow end and a deep end, add the two depths together and divide by 2.
Example: For a pool with a shallow end of 3′ and a deep end of 8′, the Average Depth = (3 + 8) ÷ 2 = 5.5′.
Round Pools
Formula
3.14 x Radius x Radius x Average Depth x 7.5 = Volume (Gallons)
Radius Calculation: Radius equals the diameter divided by 2.
Example: For a pool with a 16′ diameter, the radius is 16 ÷ 2 = 8′.
Oval Pools
Formula
3.14 x Length x Width x 0.25 x Average Depth x 7.5 = Approximate Volume (Gallons)
Kidney-Shaped Pools
Formula
(A + B) x Length x 0.45 x Average Depth x 7.5 = Approximate Volume (Gallons)
Note: “A” and “B” are the two widest points of the kidney shape.
Irregular Shapes or Free-Form Pools
Formula
Longest Length x Widest Width x Average Depth x 5.9 = Approximate Volume (Gallons)
Filtering pool water is essential for keeping the water clean and safe for swimmers; one filter turnover tends to remove 37% of contaminants. Subsequent turnovers gradually increase the filtration efficiency, with 86% filtration after two turnovers and 98% after four. Many codes require at least four turnovers every 24 hours in commercial pools.
Since different types of water use have varying degrees of contamination, the optimal turnover rate must be adjusted to account for water volume, activity levels, and contamination load.
The Importance of Knowing Your Pool’s Turnover Rate:
Featured Flow Meters
Commercial use
F-300
Pitot Tube Acrylic Flow Meter
| GPM | LPM |
|---|---|
| 2 - 1900 | 8 - 7200 |
| PSI | Bar |
| 75 | 5.2 |
| Pipe Sizes | |
| 1”, 1¼”, 1½”, 2”, 2½”, 3”, 4”, 6”, 8” | |
Residential use
R-300
FLOWREAD™ Residential Pool Flow Meter
| GPM | LPM |
|---|---|
| 10 - 150 | 37.8 - 567 |
| PSI | Bar |
| 75 | 5.2 |
| Pipe Sizes | |
| 1½”, 2”, 2½” | |
