Pipe Volume and Flow Rate Calculator
Works out pipe contents, water velocity and flow in other units.
Water in the pipe
— L
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Water velocity — m/s
Flow per hour — L/h
Flow in US gallons a minute — gpm
Time for water to travel the pipe — s
The formula
volume = π ÷ 4 × d² × length velocity = flow ÷ area
Use the inside diameter, since a nominal pipe size can differ from it.
What to watch out for
The travel time is how long you wait for hot water to arrive, while the cold in the pipe runs off.
Frequently Asked Questions
How much water is in 20 m of 22 mm pipe?
7.60 litres, taking 22 mm as the inside diameter.