Pipe Flow Calculator

Head Loss (hf) = f × (L/D) × (V2 / 2g) and Q = A × V


Head Loss:
Flow Rate (Q):

Introduction to Pipe Flow

Pipe flow refers to the fluid flow within a closed conduit, such as a pipe. It is a critical concept in various fields, including civil engineering, mechanical engineering, and environmental engineering. Understanding pipe flow is essential for the design and operation of numerous systems like water supply, sewage, and oil transport.

What Is Pipe Flow?

Pipe flow describes the movement of liquids and gases within a pipe. It can be characterized by parameters like flow rate, velocity, pressure changes, and energy loss. The behavior of the flow depends on factors such as the fluid’s properties, pipe material, diameter, length, and the presence of any fittings or valves.

Key Equations and Concepts

Darcy-Weisbach Equation

This equation estimates the head loss due to friction in a pipe:

hf = f × (L/D) × (V2 / 2g)
  • hf = Head Loss
  • f = Friction Factor
  • L = Length of Pipe
  • D = Diameter of Pipe
  • V = Velocity of Fluid
  • g = Acceleration due to Gravity

Continuity Equation

For incompressible fluids, the mass flow rate remains constant:

Q = A × V
  • Q = Flow Rate
  • A = Cross-sectional Area
  • V = Fluid Velocity

Applications of Pipe Flow

Understanding pipe flow is crucial in:

  • Designing water supply and wastewater removal systems.
  • Managing irrigation systems in agriculture.
  • Developing oil and gas distribution networks.
  • Designing HVAC systems in buildings.

Factors Affecting Pipe Flow

Several factors influence pipe flow:

  • Pipe Diameter and Length: Larger diameters reduce resistance to flow, while longer pipes increase it.
  • Fluid Properties: Viscosity and density of the fluid directly impact flow behavior.
  • Pipe Roughness: The inner surface texture can affect flow resistance.
  • Flow Velocity: Higher velocities can lead to turbulent flow, affecting pressure loss.


Pipe flow is a vital area of study in fluid mechanics, with wide-ranging applications in engineering and environmental science. Proper understanding and calculation of pipe flow parameters are essential for efficient system design and operation.