Colebrook Equation

Calculate friction coefficients for turbulent fluid flow in ducts, tubes, and pipes using the Colebrook equation. This tool is used for determining resistance and pressure loss in ventilation systems, pipes with water or oil, and compressed air applications.

Calculator

Inputs

Reynolds Number (Re) (dimensionless)

Surface Roughness (k) (m)

Hydraulic Diameter (dh) (m)

Results

Friction Coefficient (λ)-- dimensionless

Relative Roughness (k/dh)-- dimensionless

Parameter	Value	Unit
Reynolds Number	inputs.reynolds_number	dimensionless
Surface Roughness	inputs.roughness	m
Hydraulic Diameter	inputs.hydraulic_diameter	m
Relative Roughness	outputs.relative_roughness	dimensionless
Friction Coefficient	outputs.friction_coefficient	dimensionless