For educational use only — not for projects without review by a qualified professional engineer. The author takes no liability.
Pump Curve Transformation Calculator
Re-scale a pump H–Q curve for new speed or impeller diameter (affinity laws), with viscous-fluid correction — Affinity Laws / ANSI–HI 9.6.7
Base Pump Curve (test — water)
Flow QHead HEfficiency % (optional)NPSHr (optional)
Enter the manufacturer pump curve (water). Efficiency and NPSHr are optional. Efficiency drives shaft power and locates the BEP; enter NPSHr (in head units) only if you want it transformed too. NPSHr is scaled by speed² only — trim and viscosity effects on NPSHr are not modelled, so always confirm NPSHr with the pump supplier. Add more rows as needed.
Adjustments to apply
Pick what you want to transform — choose any combination. Only the inputs you need will appear below.
Fill in all fields to calculate automatically.
Select one or more adjustments on the left — speed, impeller, density, or viscosity — and the transformed curve and chart will appear here automatically.
To see the guide for this calculator, refer to the article below:
Reference: Pump Curve Correction Calculator: Speed, Impeller, Density & Viscosity Adjustments
