Pipe Flow Calculator (Hazen-Williams)
Calculate water flow rate and velocity in pipes using Hazen-Williams equation
About this calculator
The Pipe Flow Calculator using the Hazen-Williams equation helps engineers, plumbers, and hydraulic professionals determine water flow rates and velocities in pressurized pipe systems. This widely-accepted empirical formula accounts for pipe diameter, length, roughness coefficient, and pressure loss to provide accurate flow calculations. Essential for water distribution system design, irrigation planning, and plumbing projects, it ensures proper pipe sizing and optimal system performance while meeting flow requirements and pressure standards.
How to use
Enter the pipe diameter, length, and Hazen-Williams roughness coefficient (C-value) for your pipe material. Input either the pressure drop or desired flow rate, depending on what you want to calculate. The calculator will instantly compute the missing values including flow rate, velocity, and head loss using the Hazen-Williams equation.
Frequently asked questions
What is the Hazen-Williams C coefficient?
The C coefficient represents pipe roughness and material type. Common values: PVC/plastic (150), new steel (120), old steel (80-100), cast iron (100-130).
What pipe materials can I use this calculator for?
This calculator works for any pressurized water pipe including PVC, steel, copper, cast iron, and HDPE, as long as you use the correct C coefficient.
Is this calculator accurate for all flow conditions?
The Hazen-Williams equation is most accurate for water at normal temperatures in pipes 2 inches or larger with turbulent flow conditions in pressurized systems.