Pool Fill Time Calculator
Find out how long it will take to fill your pool with a garden hose and what the water will cost. Enter the volume or the pool's dimensions, then your hose flow rate or a simple bucket test.
Last updated:
(shallow + deep) ÷ 2, to the water line, not the top of the wall.
For a top-up, enter how full the pool is now.
Time it with the hose fully open, the way you will fill the pool.
Hoses on separate spigots add up only if your water supply keeps up; test each one.
From your water bill. Add sewer charges only if your utility bills them on fill water.
How to use the Pool Fill Time Calculator
- Choose units and enter the pool volume, or its shape, size and average water depth.
- Measure your flow: time how many seconds the hose takes to fill a bucket, or enter a known GPM.
- Add more hoses if you will fill from several spigots.
- Enter your water price from your bill to see the cost (optional).
- Read the fill time, the finish time and the table for faster or slower flow.
Pool fill time formula
Fill time (minutes) = water needed ÷ flow rate
With US units, water is in gallons and flow in gallons per minute (GPM). In metric, use liters and liters per minute. To get the volume from the size of the pool:
- Rectangle: length × width × average depth × 7.48 = gallons
- Round: 3.1416 × (diameter ÷ 2)² × average depth × 7.48
- Oval: 3.1416 × (length ÷ 2) × (width ÷ 2) × average depth × 7.48
In metric, the same areas in m² × depth in m × 1,000 give liters. Example: a 16 × 32 ft pool, 4.5 ft average depth, holds 16 × 32 × 4.5 × 7.48 = 17,235 gallons. At 10 GPM it takes 1,724 minutes, about 28 hours 44 minutes.
Fill time by pool size and flow rate
| Pool volume | 6 GPM | 8 GPM | 10 GPM | 12 GPM | 2 hoses at 10 GPM |
|---|---|---|---|---|---|
| 5,000 gal | 13.9 h | 10.4 h | 8.3 h | 6.9 h | 4.2 h |
| 10,000 gal | 27.8 h | 20.8 h | 16.7 h | 13.9 h | 8.3 h |
| 15,000 gal | 41.7 h | 31.3 h | 25.0 h | 20.8 h | 12.5 h |
| 20,000 gal | 55.6 h | 41.7 h | 33.3 h | 27.8 h | 16.7 h |
| 30,000 gal | 83.3 h | 62.5 h | 50.0 h | 41.7 h | 25.0 h |
Tips for filling a pool
- Do the bucket test with the hose you will actually use. Hose length, kinks, spray nozzles and the time of day (neighborhood water demand) all change the flow.
- Remove the nozzle and use the widest, shortest hose you have for the fastest flow.
- Fill to the middle of the skimmer opening, not to the top of the wall; use that water line for your depth measurement.
- Set reminders to check the level, especially overnight, so the pool does not overflow.
- Test the fill water once the pool is full. Tap and well water vary in pH, alkalinity, hardness and metals, and the first chemical balance sets up the season.
Frequently asked questions
How long does it take to fill a pool with a garden hose?
Divide the pool volume by the hose flow rate. A typical garden hose delivers somewhere around 6 to 12 gallons per minute, so a 15,000 gallon pool at 10 GPM takes 1,500 minutes, which is 25 hours. A 20,000 gallon pool at 8 GPM takes about 42 hours.
How do I measure my hose flow rate?
Do a bucket test: open the hose fully, time how many seconds it takes to fill a bucket of known size, then divide the bucket's gallons by the seconds and multiply by 60. A 5 gallon bucket that fills in 30 seconds means 10 gallons per minute.
Does using two hoses fill the pool twice as fast?
Only if your water supply can deliver both at full flow. Two hoses on spigots fed by the same small supply line share the pressure, so each may run slower. Do a bucket test on each hose while both are running and add the results.
How do I calculate pool volume from dimensions?
Multiply the surface area by the average water depth and by 7.48 gallons per cubic foot. Rectangle area is length × width, round is π × radius², and oval is π × half length × half width. In metric, cubic meters × 1,000 gives liters.
How much does it cost to fill a pool?
Multiply the gallons by your water price per gallon. Water utilities usually quote a price per 1,000 gallons or per cubic meter on the bill, and some also charge sewer fees based on water use. Ask your utility whether a pool fill qualifies for a sewer credit.
Is it faster to have water delivered?
Often, yes. A bulk water truck can deliver thousands of gallons in under an hour, while a single garden hose may need a day or more. Delivery is priced per load, so compare it with your tap water cost and time.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.