Appliances & Utilities calculator
What Sump Pump Size Do I Need?
Use design sump inflow rate, vertical lift, pipe/fitting head loss to find sump pump duty point.
Enter your measurements
What Sump Pump Size Do I Need uses design sump inflow rate, vertical lift, pipe/fitting head loss and the other configured measurements to return sump pump duty point with a formula written specifically for this tool.
- Design sump inflow rate — Required
- Vertical lift — Required
- Pipe/fitting head loss — Required
- Flow safety factor — Required
Sump pump duty point
Enter the measurements above to calculate sump pump duty point.
How the calculation works
V9 calculation: requiredFlow=inflowRate×safetyFactor; totalDynamicHead=verticalLift+pipeFrictionHead. The result is reported as sump pump duty point.
Worked example
Example: Design sump inflow rate = 0.5 L/s; Vertical lift = 50 cm; Pipe/fitting head loss = 50 cm; Flow safety factor = 1. Result: Required Flow = 0.5 L/s; Total Dynamic Head = 100 cm.
Before you decide
Enter the dimensions that will exist in real use, not an approximate catalogue category. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what sump pump size do i need, the limiting result on this page is sump pump duty point.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Sump Pump Size calculator tell me?
It returns sump pump duty point from the measurements entered on this page. The calculation is specific to sump pump size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for sump pump size?
Measure design sump inflow rate, vertical lift, pipe/fitting head loss, flow safety factor. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the sump pump duty point?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned sump pump duty point while allowing for the clearances, tolerances or ratings shown by its manufacturer.