Well Pump Size Calculator
Estimate preliminary well-pump total dynamic head, hydraulic power, input horsepower, daily water delivery and energy cost.
Default project preview
1.07 hp
Pressure head
92.3 ft
Hydraulic power
438 W
Input power
0.8 kW
Daily delivery
1,200 gal
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Target flow
Enter this project assumption in gal/min. The current imperial default is 10 gal/min.
Vertical lift
Enter this project assumption in ft. The current imperial default is 120 ft.
Required delivery pressure
Enter this project assumption in psi. The current imperial default is 40 psi.
Pipe and fitting head loss
Enter this project assumption in ft. The current imperial default is 20 ft.
Overall pump efficiency
Enter this project assumption in %. The current imperial default is 55 %. Minimum: 1. Maximum: 100.
Operating time
Enter this project assumption in hours/day. The current imperial default is 2 hours/day. Minimum: 0. Maximum: 24.
Electricity price
Enter this project assumption in per kWh. The current imperial default is 0.18 per kWh. Minimum: 0.
How to read the outputs
Pressure head
from delivery pressure. Default preview: 92.3 ft.
Hydraulic power
water power only. Default preview: 438 W.
Input power
55% efficiency. Default preview: 0.8 kW.
Daily delivery
2 operating hours. Default preview: 1,200 gal.
Daily electricity
estimated input energy. Default preview: 1.59 kWh.
Daily energy cost
entered rate. Default preview: $0.29.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Total dynamic head = vertical lift + pressure head + pipe losses. Hydraulic power = water density × gravity × flow × head. Input power divides by efficiency.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 29, 2026
This calculator estimates a well-pump duty point from required flow, pumping level, pressure target and entered losses. It does not assess well yield, water quality, electrical starting or pump installation.
Calculation steps
- 1Determine required peak flow.
- 2Measure pumping water level under demand, not only static level.
- 3Convert pressure requirement to head.
- 4Add elevation and friction, then select from the pump curve at that duty point.
Worked numerical example
A system needing 10 gpm with 120 ft pumping lift, 46 psi pressure target and 15 ft estimated friction has a total head near 241 ft of water before additional allowances.
Purchasing and rounding
Pump horsepower alone is not a selection method. The pump, motor, cable, controls, drop pipe and pressure tank must work together at the actual head and well conditions.
Interpret the result
A pump curve shows delivered flow at head. A model with a high zero-head flow may provide much less at deep-well conditions.
Page-specific assumptions
- Pumping level is representative.
- Flow demand is realistic.
- Friction estimate includes the installed pipe and fittings.
- Well yield can sustain the selected flow.
Common mistakes
- Using static water level.
- Selecting by horsepower only.
- Ignoring pressure requirement.
- Choosing flow above sustainable well yield.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
FAQ
Well Pump Size Calculator questions
What is total dynamic head?+
It is the combined lift, required pressure head and friction losses the pump must overcome at the design flow.
Why is well yield important?+
A pump should not remove water faster than the well can reliably produce without excessive drawdown.
Can horsepower alone select the pump?+
No. The pump curve must deliver the required flow at the calculated head.