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Chemical EngineeringP0

Pressure Drop Calculator (Darcy-Weisbach)

Calculate pressure drop in a pipe using the Darcy-Weisbach equation: ΔP = f × L/D × ρv²/2.

Inputs
Enter your values below

Darcy friction factor (typically 0.01-0.05 for industrial pipes)

Result
Pressure Drop
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Enter values and click Calculate
Formula
friction × length ÷ diameter × density × velocity² ÷ 2 ÷ 1000
Result unit: kPa

Darcy-Weisbach equation: ΔP = f × (L/D) × (ρv²/2). The /1000 converts Pa to kPa. L and D are in meters (auto-converted), v in m/s, ρ in kg/m³.

Introduction

Calculate pressure drop (head loss) in a straight pipe using the Darcy-Weisbach equation. This is the most accurate method for single-phase incompressible flow in pipes.

Calculation Example

100m of 100mm pipe, water at 2 m/s, f=0.02 → ~40 kPa pressure drop

Inputs: friction=0.02, length=100, diameter=100, velocity=2, density=1000
Result: 40 kPa

Engineering Applications

  • •Piping system design
  • •Pump head calculation
  • •Hydraulic analysis
  • •Process piping

Frequently Asked Questions

What is the Darcy friction factor?

The Darcy friction factor f depends on Reynolds number and pipe roughness. For turbulent flow it typically ranges from 0.01 to 0.05.

How accurate is Darcy-Weisbach?

It is the most accurate general equation for pressure drop in pipes, valid for all flow regimes when the correct friction factor is used.

Related Calculators

Pipe Flow CalculatorReynolds Number CalculatorDarcy-Weisbach Pressure Drop Calculator

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Disclaimer: Calculations are for reference and educational purposes only. Always verify results independently for engineering design. See full disclaimer.