Find Your System’s Sweet Spot, Interact Below to See How Flow and Head Align

This interactive chart compares your pump curve and system curve to reveal the operating point, the exact flow and head where your pump and system work in balance. Adjust parameters such as pipe diameter, system length, static head, and VFD speed to see how each factor influences total dynamic head and overall system performance in real time.

More tools below:

Pump Sizing Calculator

Pump Sizing Calculator

TDH, NPSHa, driver power, and flow unit conversions
TDH = Static Head + Friction Head + Pressure Head
Vertical distance between fluid source and discharge point
ft
Total friction losses through pipe, fittings, and valves
ft
Leave at 0 if suction and discharge pressures are equal
ft
Total Dynamic Head
0 ft
Meters
0 m
PSI
0 psi
Bar
0 bar
Select a pump whose operating point falls near the BEP zone on the curve to the right.
NPSHa = Atm Head +/- Suction Head - Friction - Vapor Pressure
Standard = 33.9 ft at sea level
ft
Positive above centerline, negative below
ft
Friction in suction piping only
ft
Water at 68°F = 0.78 ft
ft
From manufacturer data sheet
ft
NPSHa
0 ft
NPSHr
0 ft
NPSH Margin
0 ft
Cavitation Risk
ANSI/HI recommends NPSHa exceed NPSHr by at least 1.6 ft or 10 to 20%.
BHP = (Flow x TDH x SG) / (3960 x Efficiency)
GPM
ft
Typical centrifugal pump: 70 to 85%
%
Water = 1.0
SG
Required BHP
0 hp
Required kW
0 kW
Recommended Motor
0 hp
Service Factor
1.15 SF
Motor size includes a 1.15 service factor. Confirm with manufacturer for your duty cycle.
GPM
0
L/min
0
m³/h
0
L/s
0
CFM
0
Pump Curve
Enter TDH values and hit Calculate to see the curve

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Changes in System Curve

  • Valve changes, fouling, and added pipe length or fittings increase head losses.
  • When the system curve shifts upward, flow decreases. When it shifts downward, flow increases.
  • Always ensure pump runout and minimum flow limits are maintained to protect equipment.

Advanced Pump and System Curve Simulator

Model your flow and head performance using real engineering principles. Adjust pipe diameter, material roughness, static head, and speed control to visualize your system’s true operating point.