Sump Pump Sizing Calculator
Required sump-pump flow and head from inflow rate, lift and discharge run.
Sump pumps are rated at zero head — a '4,000 GPH' pump may move half that at 3 m lift. Always read the maker's flow-vs-head chart at YOUR TDH.
Formula
Sump Pump Sizing Calculator is a free sump pump size for pump engineers, plumbers and plant designers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Sump Pump Sizing Calculator
Required sump-pump flow and head from inflow rate, lift and discharge run. The calculation implements Q_pump = 1.5×inflow; TDH ≈ lift + friction(run) + check-valve loss (Sump & Sewage Pump Manufacturers Assoc. guidance). Sump pumps are rated at zero head — a '4,000 GPH' pump may move half that at 3 m lift. Always read the maker's flow-vs-head chart at YOUR TDH.
How to use Sump Pump Sizing Calculator
- 1Enter Peak water inflow in L/min (Measure: how many cm the pit rises per minute × pit area).
- 2Enter Vertical lift in m.
- 3Enter Horizontal discharge run in m.
- 4Read Required pump flow (with 1.5× margin), Approx. TDH instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Sump Pump Sizing Calculator?
- ✓Implements the standard formula — Q_pump = 1.5×inflow; TDH ≈ lift + friction(run) + check-valve loss
- ✓Reference cited on-page: Sump & Sewage Pump Manufacturers Assoc. guidance
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Sump Pump Sizing Calculator use?+
It computes Q_pump = 1.5×inflow; TDH ≈ lift + friction(run) + check-valve loss, per Sump & Sewage Pump Manufacturers Assoc. guidance. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Sump pumps are rated at zero head — a '4,000 GPH' pump may move half that at 3 m lift. Always read the maker's flow-vs-head chart at YOUR TDH.
Can I use this for pump selection?+
Use it to establish the duty (flow, head, NPSH, power) and then pick a pump whose curve passes through that point near best efficiency. The tool gives you the engineering numbers a supplier will ask for.
Is the Sump Pump Sizing Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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