NPSH Calculator

Will your centrifugal pump cavitate? NPSH Calculator answers that question with your real suction data. Enter your suction line (length, flow, diameter, material and fittings) and the site conditions (liquid temperature, altitude, suction static head). The app calculates the NPSH available at the pump suction, compares it with the NPSH required by your pump and gives you a clear verdict. CAVITATION CHECK + NPSH CURVE • Color-coded verdict: OK, Marginal or Cavitation • Full NPSH available vs. flow curve with your pump's NPSHr overlaid • Maximum safe flow: the exact point where NPSH available drops below NPSHr ACCURATE HEAD LOSS AT ANY TEMPERATURE • Darcy-Weisbach friction (Swamee-Jain), not a fixed 20 °C formula • Water density, viscosity and vapor pressure computed from the temperature (0–100 °C) • Reynolds number and flow regime • 14 pipe materials with real roughness, or your own value • Suction fittings with K coefficients: foot valve, check valve, elbows, tees, reducers, valves REPORTS AND PROJECTS • Export a complete PDF report with inputs, results, verdict and curve • Save and reopen projects by name NPSH INDUSTRIAL (in-app purchase) • 20 industrial fluids: seawater, glycols, caustic soda, gasoline, diesel, crude oil, solvents, sulfuric acid, and saturated LPG (propane, butane), ammonia, CO2 and R-134a, plus a custom fluid • Atmospheric, pressurized and saturated tank modes, with the saturated case handled correctly US and SI units with automatic conversion. Available in 9 languages. Works offline. Note: intended for preliminary calculations and education. Always confirm final designs and pump selections with a qualified engineer and the pump manufacturer.