Water Flow Rate Calculator
Calculate water flow from a measured volume and time, estimate pipe velocity, target fill time, daily volume and water cost.
Default project preview
10 gal/min
Litres per minute
37.85 L/min
Flow per hour
600 gal/h
Pipe velocity
7.26 ft/s
Target fill time
10 min
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Flow = measured volume ÷ collection time. Pipe velocity = volumetric flow ÷ internal pipe area. Target fill time = target volume ÷ measured flow.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Water Flow Rate Calculator questions
Why should the test use the actual outlet?+
Fittings, hoses, valves and pressure losses at that outlet affect the measured flow.
Does flow rate equal water pressure?+
No. Pressure is available force, while flow is volume delivered over time; the two interact through system resistance.
Why is internal diameter important?+
Pipe velocity depends on the true internal flow area, which can differ from nominal pipe size.