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This spring rate constant calculator will determine any of the values remaining by changing one of the variables then select the "calculate: button for the selected variable.
This calculator will calculate (estimate) the Spring Rate (k) of a extension spring. Spring rate is best determined by test and measurement techniques.
Equation: k = Gd^{4}/8nD^{3}
Where:
k = Spirng Constant, pounds of load per inch of deflection
G = modulus of rigidity
of spring material, pounds per square inch
d = wire diameter, inches
n = number of active coils, which is the number of coils subjected to flexure (always less than the total number of coils)
D = mean coil diameter, inches = Outer Diameter  Wire Diameter
Open Extension Spring Rate "k" Constant Calculator
Extension Spring Design Suggestions
