Pump Affinity Laws

Estimate pump affinity laws with a transparent calculation and custom visualization.

Estimated new pump flow
8 flow units
Inputs
Enter the old speed for this engineering estimate.
Enter the new speed for this engineering estimate.
Enter the old flow for this engineering estimate.
Enter the old head for this engineering estimate.
Enter the old power for this engineering estimate.
Results & Graph
Estimated new pump flow
8 flow units

Estimated new pump flow

Graph 1 • Input-to-result flow Shows the calculated components and current result from this tool.
Estimated new pump flowSpeed ratio0.8Flow8Head19.2Power1.0Estimated new pump flow: 8 flow units
Graph 2 • Modeled quantities Compares the values returned by the active calculation.
Speed ratio 0.8 Flow 8 Head 19.2 Power 1.0
Graph 3 • Calculation checkpoints Displays the engine’s named calculation points in order.
0ratio 10.4ratio 20.7ratio Speed ratio: 0.8 ratio 0.8 Speed ratio Flow: 8 ratio 8 Flow Head: 19.2 ratio 19.2 Head Power: 1.024 ratio 1.0 Power
Summary: For the same impeller and fluid, similarity laws estimate head ×0.64 and power ×0.512.
Summary: For the same impeller and fluid, similarity laws estimate head ×0.64 and power ×0.512.
⚠️ Affinity laws are approximate. System curve, efficiency, cavitation margin, motor limits, and manufacturer operating envelope must be checked.

Formula & Mathematical Methodology: Pump Affinity Laws formula

See the calculation steps and assumptions shown with the result.
See the calculation steps and assumptions shown with the result.
  • oldSpeed: User-entered old speed (rpm).
  • newSpeed: User-entered new speed (rpm).
  • oldFlow: User-entered old flow (m³/h).
  • oldHead: User-entered old head (m).
  • oldPower: User-entered old power (kW).

Rounding: Displayed result is rounded for readability.

Worked Example: undefined

Use the starting values as a screening case.

  1. Enter project-specific measurements and properties.
  2. Review assumptions and limitations.
  3. Compare the visualization with an independent engineering check.
Result: Estimates pump affinity laws for the entered case.

Frequently Asked Questions

Can I use this as a final design check?

No. It is a preliminary calculation and does not replace applicable codes, manufacturer data, or qualified engineering review.

Science & Engineering • Engineering Guide

How to Use the Pump Affinity Laws: Practical Guide & Visual Analysis

Use this engineering calculator for an initial screening estimate. Results are calculated locally from the values you enter. Whether you are researching pump affinity laws, pump affinity laws calculator, pump affinity laws estimate, this interactive tool helps you calculate a preliminary pump affinity laws estimate from user-entered engineering inputs.

Interpreting the 3 Custom Visual Graphs & Key Outputs

As you adjust Old Speed, New Speed, Old Flow, Old Head, the calculator immediately computes Calculated engineering estimate, Input component breakdown, Calculation profile and updates all three domain-specific SVG charts in real time. Instead of relying on a single static figure, you can inspect the primary domain diagram, component breakdown, and multi-point trajectory curve to see how changing your inputs shifts the final result. Use the Compare (up to 3 scenarios) button to evaluate side-by-side variations before making a decision.

Real-World Benchmark & Planning Tips (General engineering estimate; confirm applicable standards, units, and project conditions.)

In our benchmark scenario (undefined), Estimates pump affinity laws for the entered case. Keep in mind that entered values represent the modeled system. For related calculations in Science & Engineering, explore Beam Deflection Calculator, Pump Power and Operating Cost Calculator, Three-Phase Power Calculator.