Sump Pump Size Calculator
Estimate sump-pit active volume, fill time, required pump flow, capacity margin, cycles per hour and daily water removal.
Default project preview
12 gal/min
Active pit volume
8.8 gal
Fill time
1.1 min
Pump capacity margin
+13 gal/min
Estimated cycles
37 per hour
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Active pit volume is a cylinder. Required flow = inflow × reserve factor. Cycling combines pit fill time with pump-down time based on net removal flow.
FAQ
Sump Pump Size Calculator questions
Why use pump capacity at design head?+
Published zero-head flow is higher than the flow available after vertical lift and pipe losses.
What happens if pump capacity is below inflow?+
The water level continues rising, so the pump is undersized for the entered condition.
Should a backup pump be installed?+
Backup pumping, battery power and alarms are often considered where flooding would cause significant damage.