Pipe Flow Calculator

Enter pipe diameter, flow velocity, and fluid properties to calculate flow rate, Reynolds number, and pressure drop.

Inner Diameter (mm)

Flow Velocity (m/s)

Fluid Density (kg/m³)

Dynamic Viscosity (Pa·s)

Pipe Roughness ε (mm)

Flow Rate

L/s

Flow Rate (GPM)

—

Reynolds Number

—

Friction Factor (f)

—

Pressure Drop / ft

—

Pipe Flow & Darcy-Weisbach Equation

Q = A × V = π/4 × D² × V

Re = ρVD / μ

ΔP/L = f × (ρV²) / (2D) (Darcy-Weisbach)

Flow regime.

Fluid energy.

Material stress.

Gear design.

Belt/pulley.

Unit conversion.