Pipe Pressure Loss Calculation

Conditions

Before calculating pressure drop, you can check pipe velocity or estimate pipe inner diameter from flow rate.

Item	Value	Unit
Fluid Density		kg/m³ g/cm³ g/mL
Fluid Viscosity		Pa·s mPa·s cP P
Flow Rate		m³/hr m³/min m³/s L/hr L/min L/s mL/hr mL/min mL/s
Pipe Inner Diameter		mm
Pipe Length (Including Equivalent Length)		m
Pressure Loss Unit	kPa atm bar mmHg kg/cm²

Calculate

Number of Fittings and Valves

Enter the number if needed.

Type of Fitting or Valve	Quantity
45° Elbow
90° Elbow (Standard Radius)
90° Elbow (Medium Radius)
90° Elbow (Long Radius)
90° Bend (R/D = 3)
90° Bend (R/D = 4)
180° Bend
Cross
Tee
Gate Valve (Fully Open)
Gate Valve (1/4 Closed)
Gate Valve (1/2 Closed)
Gate Valve (2/3 Closed)
Globe Valve (Fully Open)
Angle Valve (Fully Open)

Calculate

Calculation Result

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Pipe Pressure Loss Calculation Formula

This calculation determines the pressure loss (ΔP) in the pipe based on the following formula (Fanning's equation):

ΔP = 4 f ρ u2 L D

• ΔP: Pressure Loss
• f: Friction Factor
• ρ: Fluid Density
• u: Average Velocity in the Pipe
• L: Pipe Length (Including Equivalent Length from Fittings and Valves)
• D: Pipe Inner Diameter

The friction factor (f) varies with the fluid's turbulence state and is calculated using the following formula (Nikuradse's equation):

1 √f = 3.2 log10 Re √f + 1.2

The Reynolds number (Re), which determines the flow characteristics, is defined as follows:

Check the Reynolds number and flow regime

Re = ρ u D μ

• Re: Reynolds Number
• μ: Fluid Viscosity