Well Pump Size Calculator
Who it's for: Well and plumbing contractors, service technicians, and estimators.
Calculator Inputs
Quick Summary
- Built for: Well and plumbing contractors, service technicians, and estimators.
- Key outputs: Total dynamic head (TDH), Pressure head and lift head, and more.
- Use this page for early planning estimates before final code and manufacturer verification.
Inputs
- Desired flow rate (GPM)
- Static and pumping water levels (ft)
- Pressure tank cut-in/cut-out (psi)
- Elevation to highest fixture (ft)
- Estimated friction loss and safety factor
Outputs
- Total dynamic head (TDH)
- Pressure head and lift head
- Required flow
- Suggested pump HP class
How this calculator estimates results
- Converts cut-out pressure to feet of head using 2.31 ft per psi for a worst-case tank-pressure target.
- Builds lift head from pumping water level plus elevation to the highest fixture and adds estimated friction losses.
- Applies a safety factor and maps resulting TDH plus flow demand to a heuristic pump HP class.
Cross-check assumptions with Sump Pump Size Calculator for a more complete planning workflow.
Common ranges and tips
- Use measured pumping water level when possible; static level alone can understate required head.
- Friction losses vary with pipe size, fittings, and flow rate, so keep this input conservative.
- Always confirm final selection using manufacturer pump curves at your actual duty point.
- Treat this as planning guidance, not final equipment approval.
Related Calculators
FAQ
TDH is estimated from lift head, pressure head, and user-entered friction losses, then adjusted by a safety factor.
Cut-out pressure is used as a worst-case operating target so the estimate reflects higher required head conditions.
No. Final model selection requires manufacturer pump curves and verified field conditions.
High-head scenarios should be validated with detailed pump-curve analysis and often require more specific system design.
Disclaimer: Use results for planning only. Final design and installation decisions must follow local code and manufacturer documentation.
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