Pump Horsepower Calculator
Free pump horsepower calculator for pump kW, HP, motor sizing, flow, head, and efficiency planning. Includes formulas, sample data, warnings, related.
Inputs
Forms are empty on load. Use sample data to preview the workflow or enter your own project values.
Learn more
Formula logic, use cases, assumptions, and limits for this tool.
How this tool helps
Use this for preliminary pump motor sizing from flow and head. Final selection should be made from manufacturer pump curves, NPSH checks, duty/standby strategy, voltage, starting method, and project specifications.
Common search intent
This page supports practical searches for pump horsepower calculator, free MEP calculator, design estimate, engineering planning, and construction coordination checks.
Assumptions and limits
This is a planning-level calculator. Final engineering decisions must be verified against authority requirements, project specifications, manufacturer data, installation conditions, and approved standards.
Keyword and design notes
Common searches include pump horsepower calculator, pump power calculator, pump kW calculator, pump motor sizing, and flow head horsepower. Use this page to estimate the motor power implied by flow and total dynamic head before selecting a pump curve and checking NPSH, efficiency, and duty point. The calculated horsepower is a starting point only; the selected motor should also allow for service factor, starting method, power supply, and pump operating range.
Calculation methodology
Hydraulic kW = density x gravity x flow x head. Shaft and motor power adjust for efficiency and motor margin.
Inputs are treated as planning assumptions. The calculator shows warnings when entered values fall outside practical thresholds or selected standard-profile limits.
Version history
- v1.3.6-prelaunch: Added methodology, standard profile support, version notes, and direct PDF report download.
- v1.3.5: Calculator page added with sample data, warnings, and print-ready report layout.
Stage 2 roadmap: optional saved projects, dashboards, and shared calculation history without forcing login for free use.
Trust and verification
Every result includes assumptions, warning logic, and a downloadable report. Final engineering decisions still need qualified review, local authority approval, manufacturer data, and project specifications.
Worked example
Use the sample data button to load a realistic scenario, then download the PDF report to review inputs, results, methodology, warnings, and disclaimers in one place.
Input definitions and typical values
These notes explain what each input means and which values usually produce a more reliable planning result.
Flow m3/h
Fluid flow rate. Use demand, fixture-unit conversion, process requirement, or load-derived flow as applicable.
Total dynamic head m
Total dynamic head. Include static lift, friction loss, fittings, valves, and required residual pressure.
Pump efficiency %
Efficiency percentage. Pumps, fans, motors, and systems should use manufacturer or design-stage assumptions.
Motor margin %
Percentage adjustment used for diversity, derating, margin, reserve, or contingency. Use project-specific assumptions where available.
Practical verification checklist
- Confirm the selected standard profile is suitable for the project location and authority.
- Replace sample values with project drawings, schedules, equipment data, or measured site values.
- Review warnings, methodology, and PDF report before using the result outside early planning.
- Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.