Calculate fluid flow rate, velocity, and pipe sizing for hydraulic and pneumatic systems. Essential engineering tool for flow analysis and pipe design.
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Enter Velocity + Area, or Mass Flow + Density
Select whether to calculate flow rate, velocity, pipe diameter, or pressure drop based on your needs.
Input pipe diameter, length, and material properties including roughness factor.
Enter fluid density, viscosity, and operating conditions (temperature, pressure).
Enter known values such as flow rate, velocity, or pressure difference.
Review calculated values, Reynolds number, and flow regime (laminar or turbulent).
Smooth, predictable flow with low mixing. Pressure drop is directly proportional to velocity. Common in viscous fluids or small pipes.
Unstable flow regime between laminar and turbulent. Flow characteristics can vary and are difficult to predict accurately.
Chaotic flow with good mixing. Pressure drop increases with velocity squared. Most common in water and air systems.
May cause erosion, noise, or water hammer. Consider larger pipe diameter or flow control measures.
Relate Q, v, A, density, and mass flow for steady, incompressible cases. Handy for quick pipe and duct checks.
Relate volumetric flow, velocity, and cross‑sectional area with convenient unit handling.
Solve any variable from the others.
L/s, m³/h, gpm, ft/s, cm², in².
Simple sizing checks.
Flow rate calculator, velocity, area, gpm to lpm
Important: This flow rate calculator is designed for educational and preliminary fluid mechanics analysis purposes using standard flow equations and assumptions of steady, incompressible flow through idealized systems. While calculations are based on established fluid mechanics principles, real-world fluid systems involve complex factors including compressibility effects, turbulence, pipe fittings, elevation changes, temperature variations, and fluid properties that significantly affect actual flow rates. For piping system design, pump selection, process engineering, or any fluid system requiring accurate flow predictions, consult qualified mechanical or chemical engineers who can perform comprehensive fluid analysis accounting for system-specific conditions, safety factors, and applicable engineering standards.