Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Plumbing & Piping
Sump Pump Sizing Calculator — GPH by Basement Area
GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
Size sump pump capacity from catchment area and lift head. Planning estimates only — verify measurements and local codes on site.
Inputs
2005000
0.253
320
Smart analysis
Recommendations
Tailored to your live inputs and result—guidance only, not professional advice.
- Interpret
Treat this as a planning estimate
Primary result: Pump class GPH = 698. Re-run with optimistic and pessimistic inputs to understand the range—not just a single point.
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Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Basement sq ft
The “Basement sq ft” value used in this tool’s formula. Adjust it to see results update live.
Design rainfall (in/hr)
The “Design rainfall (in/hr)” value used in this tool’s formula. Adjust it to see results update live.
Head height (ft)
The “Head height (ft)” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
Size sump pump capacity from catchment area and lift head. Planning estimates only — verify measurements and local codes on site. GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment. Example: 800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
Example: 800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
When to use this Sump Pump Sizing
Common use cases
- Size sump pump capacity from catchment area and lift head.
- Sanity-check with this case: 800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
- The relationship is: GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
Localized examples
- Plumbing & Piping: the example on this page uses the same formula as the widget.
What you get
- Fields: Basement sq ft, Design rainfall (in/hr), Head height (ft)
- GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
- Example on the page: 800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
How to Calculate Sump Pump Sizing Step-by-Step
- 1Enter Basement sq ft, Design rainfall (in/hr), Head height (ft). Use the values you have, not a catalog average, unless that is all you know.
- 2GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
- 3Worked case: 800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
- 4Buy materials after you walk the job. This is a first-pass quantity, not a purchase order.
Governing formula
GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
800 sq ft basement, 1 in/hr, 8 ft head → ~2,400+ GPH pump class.
Example: set Basement sq ft = 800, Design rainfall (in/hr) = 1, Head height (ft) = 8, then read the result.
Variable definitions
- basementSqFt
Basement sq ft
The “Basement sq ft” field. Default 800; typical range 200–5000.
- rainfallInPerHr
Design rainfall (in/hr)
The “Design rainfall (in/hr)” field. Default 1; typical range 0.25–3.
- headHeightFt
Head height (ft)
The “Head height (ft)” field. Default 8; typical range 3–20.
- The takeoff (GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.) ignores waste, code, and what you find when you open the wall. Measure twice on site.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
GPH ≈ basement sq ft × in/hr rainfall factor × head adjustment.
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Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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