AIEngineeringTool

Spring Rate Calculator

Calculate the rate of a close-coiled helical compression spring.

Wire diameter: 5 mm
Live concept view — geometry scales with the entered design condition.

Calculate the rate of a close-coiled helical compression spring.

Design inputs

Enter known values using the units shown. Results and the live SVG view update immediately.

PRELIMINARY RESULT

Spring rate17.99 N/mm

Spring index: 7.00

Spring rate
17.99 N/mm
Spring index
7.00

Calculation detail

Formula: k = Gd⁴ / (8D³N)

Spring rate is calculated from material shear modulus, wire diameter, coil diameter and active coils.

FORMULA VERIFICATION

Units, scope and reference

Reference: Shigley, Mechanical Engineering Design, close-coiled helical compression springs.

Internal unit basis: N/mm², mm. Outputs: N/mm.

Valid conditions: Positive geometry and shear modulus; close-coiled round wire.

Limitations: No Wahl stress, solid height, buckling or fatigue check.