Work out shower flow rate instantly with clear inputs, formula shown and shareable results.
The bucket test measures shower flow directly: litres collected divided by seconds, scaled to a minute. From there the water and energy cost of a shower follows immediately. Low-flow heads deliver 6-9 L/min while an unrestricted mixer can exceed 15 L/min.
Flow rate
L/min = litres collected x 60 / seconds; GPM = L/min / 3.785
Per shower
Litres = flow L/min x shower minutes
L/min = litres collected x 60 / seconds; GPM = L/min / 3.785. The bucket test measures shower flow directly: litres collected divided by seconds, scaled to a minute.
Not necessarily. Aerating and laminar heads maintain perceived pressure by increasing exit velocity, so the reduction is mostly invisible below about 8 L/min.
This calculator takes 3 inputs: Water collected, Collection time, Typical shower length. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.