Flow Rate Calculator
Calculate fluid flow rate from volume and time, or from velocity and pipe cross-section, in litres or gallons per minute, free in your browser.
Enter Values
Minimum 0
How to use this calculator
- Enter the volume (litres) and the time (minutes).
- Read the flow rate.
How it works
Flow rate = volume ÷ time; the per-hour and per-second figures are scaled from L/min.
Worked example
200 L in 5 minutes. = 40 L/min.
Common mistakes
- Timing only part of the fill — measure a steady, full flow.
- Mixing units — keep volume in litres and time in minutes.
Frequently asked questions
How is flow rate calculated?
Volumetric flow = cross-sectional area × velocity, or volume ÷ time. A pipe's flow rises with both its bore and the fluid speed.
What units is flow rate in?
Commonly litres per minute or cubic metres per second; the tool converts between volume-per-time units.
How do I measure flow at a tap?
Time how long a bucket of known volume takes to fill, then enter both — e.g. a 10 L bucket in 30 s is 20 L/min.
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- Pipe Volume Calculator
- Acceleration Calculator
- Reynolds Number Calculator
- Specific Heat Calculator
- Speed, Distance & Time Calculator
- Kinetic Energy Calculator
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Cite this tool
Zerdly. (2026). Flow Rate Calculator. Retrieved from https://www.zerdly.com/tools/flow-rate-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.