Hazen Williams Equation Calculator

The Hazen Williams equation is a widely used method for calculating head loss due to friction in a pipe. It’s particularly useful in water flow systems, aiding engineers and designers in understanding pressure drops and ensuring efficient flow rates through pipes.

Formula: The Hazen Williams equation is expressed as:

Head Loss=4.8655×(Flow RateHazen-Williams Coefficient×Pipe Diameter1.167)1.852×Pipe LengthHead Loss=4.8655×(Hazen-Williams Coefficient×Pipe Diameter1.167Flow Rate​)1.852×Pipe Length

How to Use:

  1. Input the flow rate in gallons per minute.
  2. Provide the Hazen-Williams coefficient.
  3. Enter the pipe diameter in inches.
  4. Specify the pipe length in feet.
  5. Click the “Calculate” button to obtain the head loss.

Example: Let’s consider a scenario where:

  • Flow Rate = 100 gallons per minute
  • Hazen-Williams Coefficient = 120
  • Pipe Diameter = 6 inches
  • Pipe Length = 500 feet

Upon calculation, the head loss would be determined.


  1. What is the Hazen Williams equation used for?
    • The Hazen Williams equation is used to calculate head loss due to friction in pipes for fluid flow.
  2. How accurate is the Hazen Williams equation?
    • The equation provides reasonable estimates for head loss in many practical engineering applications, especially for water flow in pipes.
  3. Can the Hazen Williams equation be used for all fluids?
    • It’s primarily applicable to water flow; however, adjustments can be made for other fluids by altering the Hazen-Williams coefficient.
    (More FAQs can be added based on specific queries about the Hazen Williams equation.)

Conclusion: The Hazen Williams equation is a valuable tool in fluid mechanics, particularly in designing water distribution systems and estimating pressure drops in pipelines. By understanding how to use this equation and its parameters, engineers can optimize pipe systems for efficiency and reliability.