Pipe Flow Calculator
Estimate pipe flow velocity and discharge from pipe diameter, head drop, pipe length, and material roughness.
Enter the pipe dimensions and available head drop. Results update automatically when you change an input.
How to Use the Calculator
- Enter the pipe's internal diameter and total pipe length.
- Select the material to load an approximate Hazen–Williams C coefficient, or choose the custom option.
- Enter the available head drop over the stated pipe length.
- Choose the units for velocity and discharge. Results recalculate automatically.
- Use the estimate as a preliminary calculation and confirm it against project conditions and local requirements.
Assumptions and Limitations
This calculator estimates full-pipe flow using the Hazen–Williams equation. It assumes water-like fluid, steady flow, a full circular pipe, and that the entered head drop is available to overcome pipe friction over the entered length. Typical C values are approximate: pipe age, corrosion, deposits, joints, fittings, valves, and actual product specifications can change results. The calculation does not separately account for minor losses, elevation changes beyond the entered head drop, pumps, or transient flow. It is not a substitute for a detailed hydraulic design.
