Pump head and flow calculator
Calculate the head required for one documented flow condition. The result is a point to discuss against a current manufacturer curve, not a pump or motor recommendation.
Developed with AI assistance; not reviewed by a licensed well or pump professional. Educational planning only. No individual professional or AI assessment occurs. Method and sources · Conditions of use
Your planning result
Enter all six known values, choose the supported system and confirm the conditions.
ft total dynamic head
At US gpm. Display rounding makes the arithmetic readable; it is not measurement accuracy.
- Pumping water level
- ft
- Signed delivery elevation
- ft
- Net elevation head
- ft
- Required flowing pressure
- psi
- Pressure head
- ft
- Complete documented losses
- ft
- Delivery inside diameter
- in
- Mean delivery velocity
- ft/s
- Delivery velocity head
- ft
Scope used: ordinary cold water, one submerged fixed-speed pump, unpressurized well-water surface, full circular delivery pipe and one steady flow.
This is a required head-and-flow point, not the actual operating point or an equipment match. It does not choose a pump, horsepower, motor, controls or tank, and it does not establish well yield, submergence, cooling, pressure safety, electrical suitability or installation compliance.
Developed with AI assistance; no licensed professional review. Fixed educational arithmetic, not an individual AI or professional assessment. Confirm measurements, losses, source revision and equipment requirements with a qualified pump installer.
Method pump-1.0.0 · Sources checked September 8, 2026.
Goulds/Xylem TTECHWP R6, PDF pp. 3, 22 and 39 · Goulds GSSPEC R4, PDF p. 2
How to use the head-and-flow point
- Check the loss record. Goulds/Xylem TTECHWP R6 lists 6.88 ft of head loss per 100 ft for 1-inch Schedule 40 plastic pipe at 10 US gpm. Two hundred feet of straight pipe would be 13.76 ft before fittings, valves and devices. Use current applicable tables for the actual path; this tool does not estimate losses.
- Read a current curve. In the Goulds GSSPEC R4 (July 2025) 60 Hz, 3,450 RPM chart, locate the desired flow horizontally and required head vertically. Its 10GS family marks 3–16 US gpm as the recommended family flow range; the teaching example’s 10 gpm lies inside that range. This says nothing about which exact model can provide about 195.6 ft.
- Check the whole system. The desired point is not automatically the actual operating point. Have a qualified installer check the exact model curve and range, well yield, submergence and cooling, pressure limits, motor, electrical supply, controls, cycling and installation requirements.
Frequent starting is a symptom, not a diagnosis
Franklin Electric’s 2026 AIM manual says excessive cycling can damage controls and motors. Its troubleshooting table lists several possible causes of a motor starting too often, including a pressure switch problem, a stuck-open check valve, a waterlogged tank and a system leak.
Do not infer a cause or use one universal starts-per-day limit. Manufacturer limits depend on the exact motor type, phase, horsepower and controls. Record observed run and off times, flowing and resting pressure readings, and the equipment/control details for qualified service. Do not open electrical equipment or work on a pressurized or corroded tank.
Franklin 2026 60 Hz AIM manual landing page, PDF printed pp. 4, 11 and 26.
Method, assumptions and sources
This worksheet follows Goulds/Xylem TTECHWP R6: pressure head for ordinary water is 2.31 × pressure psi; mean full-pipe velocity is 0.409 × US gpm ÷ inside diameter²; velocity head is velocity² ÷ (2 × 32.16). Total head is pumping water level plus signed delivery elevation plus pressure head plus complete documented losses plus delivery velocity head.
The manual also prints a conflicting .155 × velocity² shortcut. This version uses the underlying velocity² ÷ (2g) equation with the manual’s g = 32.16 ft/s²; it does not use the apparent shortcut typo. Constants are rounded and ordinary cold water is approximated at specific gravity 1. US units only.
Pumping level means the operating water level while the selected flow occurs. Pump setting and total well depth do not replace it. Pump setting still affects drop-pipe length, submergence and the documented loss path. Every pressure, loss and velocity value must describe the same steady-flow scenario and named references.
Product bounds are 1–50 US gpm; pumping level over 0 through 2,000 ft; elevation −1,000 through +1,000 ft with positive net elevation head; pressure 0–150 psi; complete losses 0–1,000 ft; inside diameter 0.5–4 in; and computed velocity no more than 10 ft/s. These are worksheet limits, not recommended designs. Known zero is different from missing information.
Teaching example: 10 US gpm, 60 ft pumping level, +10 ft delivery elevation, 50 psi flowing pressure, 10 ft complete losses and 1.25 in actual delivery inside diameter. Velocity is 2.6176 ft/s, velocity head is about 0.1065 ft and total dynamic head is about 195.6 ft.
Primary sources: Goulds/Xylem TTECHWP R6 (December 2022, PDF pp. 3, 22, 37 and 39); Goulds GSSPEC R4 (July 2025, PDF p. 2); and Franklin Electric 2026 60 Hz AIM manual (M1311 06-26, printed pp. 4, 11 and 26). Sources checked September 8, 2026; WDG method pump-1.0.0. No manufacturer endorsement or licensed professional review is claimed.