Pool Fill Time CalculatorFree online other calculator — instant results, no sign-up
Estimate filling duration from capacity and hose flow.
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About the Pool Fill Time Calculator
The Pool Fill Time Calculator estimates how long a hose will take to fill a pool using its capacity in liters and the hose flow rate in liters per minute. With the default capacity of 48000 L and flow rate of 20 L/min, the estimated filling duration is 40 hours. Use this estimate to plan a supervised fill and allow extra time if your water flow varies.
- Pool capacity (L)
- The volume of water needed to fill the pool to its intended level, measured in liters (L), with a default of 48000.
- Flow rate (L/min)
- The rate at which the hose delivers water into the pool, measured in liters per minute (L/min), with a default of 20.
Formula and method
t = V / (60 × Q); with the default inputs, t = 48000 / (60 × 20) = 40 hours.
- tEstimated filling duration in hours.
- VWater volume to add, in liters.
- QHose flow rate, in liters per minute.
- 60The number of minutes per hour, used to convert the filling duration from minutes to hours.
Divide the volume of water needed by the hose flow rate to obtain the filling duration in minutes, then divide by 60 to convert it to hours. For the default inputs, 48000 L divided by 20 L/min gives 2400 minutes, which equals 40 hours.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Pool capacity48000 L
- Flow rate20 L/min
Results
- Result40 hours
How to use the Pool Fill Time Calculator
- 1Find the pool's capacity at its intended fill level, expressed in liters.
- 2Enter that volume in Pool capacity (L); if the pool is partly full, enter only the volume still needed.
- 3Measure or estimate the hose's delivered flow in liters per minute and enter it in Flow rate (L/min).
- 4Read the estimated filling duration; the default inputs of 48000 L and 20 L/min produce 40 hours.
- 5Plan for interruptions or changing pressure, and monitor the pool during filling to avoid overflow.
Reading your result
The result row shows the estimated filling duration in hours, not a clock time or completion date. A result of 40 hours means the hose must deliver water continuously for 40 hours at the entered rate to supply the entered volume. Pauses add to the elapsed time before the pool is full.
Limitations
The estimate assumes a constant positive flow rate, uninterrupted filling, and no water losses from leaks, evaporation, or overflow. Actual hose output can vary with water pressure, hose length, restrictions, and other household water use. Accuracy also depends on the volume entered: a pool's advertised maximum capacity may differ from its normal operating volume. The calculator does not account for local filling restrictions, water costs, or the time needed to treat and balance pool water before swimming.
Common questions
How can I measure my hose's flow rate for this calculator?+
Time how long the hose takes to fill a container of known volume. Divide the container volume in liters by the elapsed time in minutes to get L/min. Test with the same hose, tap setting, and outlet setup you will use to fill the pool.
What should I enter if my pool already contains water?+
Enter only the liters still needed to reach the intended water level, rather than the full pool capacity. The calculator treats the entered capacity as the volume to add.
Can I estimate filling time when using more than one hose?+
Yes. Enter the combined flow delivered by all hoses while they are running together. Hoses sharing a water supply may reduce each other's output, so adding measurements taken with each hose running alone can overestimate the combined flow.
Does the 40-hour result mean I can leave the hose running unattended?+
No. The result is a planning estimate, not an automatic shutoff schedule. Monitor the water level and hose placement, stop filling at the intended level, and follow local water-use rules.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.