Swimming Pool Fill Time Calculator
Estimate rectangular pool volume, litres and filling time from pool dimensions, average depth, measured hose flow and loss allowance.
Your results
Calculation breakdown
- Fill time
- length × width × average depth × 1,000 × (1 + loss allowance ÷ 100) ÷ flow ÷ 60
Worked example
An 8 m × 4 m pool averaging 1.5 m deep holds 48,000 L; with 5% allowance and 25 L/min flow it takes about 33.6 hours continuously.
Assumptions
- Pool plan and average depth form a rectangular-prism approximation.
- Measured flow stays constant and filling is permitted.
Sources
Rates effective 23 August 2026.
How this calculator works
A sloping rectangular pool can be approximated with its average water depth, producing cubic metres that convert directly to thousands of litres. Dividing allowance-adjusted litres by a measured supply flow gives continuous filling time, while local water restrictions, pool structure and commissioning remain separate checks.
Frequently asked questions
How do I estimate average pool depth?
For a simple constant slope, average the shallow and deep water depths; complex benches, steps and curves need a segmented volume estimate.
Why measure hose flow instead of using a guess?
Available flow varies with pressure, hose length, fittings and other water use, so a timed container test gives a more useful input.
Can a new pool be filled immediately?
Check the pool builder's instructions and your local water corporation's current restrictions or permit requirements before filling. Curing, finish, groundwater and water-quality requirements can also affect timing.
Content responsibility
Maintained by CalcAussie and last updated 13 October 2026. Checks applied: calculation method, worked examples, Australian terminology, material assumptions, official references where an external rule applies, and user-facing limitations.
Calculator results remain estimates based on the figures entered. Check material decisions against current official information and report a suspected error so it can be reproduced and corrected.