Calculator guide
Sump Pump Size Calculator helps you explore the stated construction question. Start with the labelled inputs, then review the method, worked example and limitations before using a result.
Formula or method
Illustrative design flow = measured inflow×(1+chosen margin/100). Report that flow at the entered total dynamic head; this tool does not calculate head losses.
How to use this calculator
- Set Measured Pit Inflow (GPM). The interface starts with 20; replace it with the value for your scenario.
- Set Total Dynamic Head (include friction) (ft). The interface starts with 10; replace it with the value for your scenario.
- Set Safety Margin (%). The interface starts with 50; replace it with the value for your scenario.
- Compare the result with the worked example, then vary one assumption at a time so you can see what changes.
Worked example
Measured 20 GPM inflow and 50% margin give 30 GPM. Entering 10 ft total dynamic head produces a comparison point of 30 GPM at 10 ft head.
Understanding the result
Compare the output with the sump pump size calculator worked example using exactly the same inputs. A different assumption or rounding convention can produce a different displayed result; the output does not establish personal or professional suitability.
Limitations and assumptions
- Total dynamic head must include vertical lift, pipe friction, fittings, and discharge losses. Consult manufacturer performance curves; a zero-head pump rating is not sufficient.
- The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.
Frequently asked questions
Which inputs should I check first?
For Sump Pump Size Calculator, check Measured Pit Inflow, Total Dynamic Head (include friction), Safety Margin. Keep the displayed units and select options consistent; do not treat default values as recommendations.
Why might my result differ from another tool?
Compare the other tool's sump pump size calculator method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.
Does a linked reference certify this result?
No. A reference can explain a formula or provide background for Sump Pump Size Calculator, but it does not endorse this website, validate personal inputs or establish professional suitability.
Sources
Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.