Frictionless Calc is a free collection of practical, browser-based engineering calculation tools. The site includes practical tools for pipe pressure drop, velocity, Reynolds number, friction factor, fitting equivalent length, liquid valve Cv, pump power, NPSH available, liquid orifice flow, and multi-layer heat transfer.
Why this site exists
Engineering calculations are easier to trust when the assumptions and intermediate values are visible. The calculator is designed to show the quantities behind the final answer, including velocity, Reynolds number, relative roughness, friction factor, fitting loss coefficients, and the separate pressure-drop contributions from pipe and fittings.
How the calculator works
The calculation runs in your browser. The current pipe pressure-drop calculator supports both US customary and SI inputs and automatically selects a straight-pipe friction method based on Reynolds number. Fitting losses are calculated with dimensionless loss coefficients and shown in a separate breakdown.
Current scope
Each tool states its own scope and assumptions. The main pressure-drop calculator currently models one constant pipe diameter per calculation; some fitting types and multi-section systems are intentionally not yet implemented.
Questions or feedback
Found a bug, have a validation case, or want to suggest another engineering calculator? Email contact@frictionlesscalc.com.