Water Velocity Calculator

Nobody wants a screaming pipe or a silent one that gathers scale. Both complaints hide behind one number - the velocity of the water inside the bore - which is easy to find and easy to miss.

Water Velocity Calculator turns flow and diameter into a velocity, converts it into the units you work in, and compares it with design guidelines so a look at the gauge settles it.

• One number: Velocity from flow and bore.
• Dual readout: fps and m/s together.
• Design check: Flags low, ideal and too-fast speeds.
• Any units: GPM, LPM, inches, mm.
• Instant: Live result as you type.
• Export: Text, CSV or JSON report.

1. Enter the flow the pipe is carrying (GPM or LPM).
2. Enter the internal bore (inches or mm).
3. Read the velocity in fps and m/s.
4. Check the verdict against the design guideline.
5. Adjust pipe size if the speed is over target.

Example 1. 6 GPM in a 0.785 in bore runs just over 3.4 fps (1.0 m/s) - a comfortable cold-supply speed.

Example 2. 10 GPM crammed through a 1/2 in bore hits over 15 fps - noisy, erosive, and well over design.

Example 3. 22 LPM in a 20 mm bore moves at about 1.2 m/s.

• Catches overspeeds: Before noise and hammer appear.
• Dual units: fps and m/s on one screen.
• Design-based: Verdict uses standard guidelines.
• Works in the field: No charts needed.
• Free and private: No uploads, no logging.