Mechanical & Civil Engineering
Helical Compression Spring Rate Calculator
Calculate the spring rate of a helical compression spring from wire diameter, coil diameter and active coils.
Your inputs
Change any value to update the result instantly.
Spring rate
14.375 lb/in
Spring index C = D/d
10
Deflection under 100 lb
6.9565 in
Active coils
10
What this calculator does
Helical Compression Spring Rate Calculator: Applies the standard machine-element relationship used in design textbooks so the capacity, rating or geometry can be worked out step by step.
What your result means
The headline figure is the capacity, rating or geometric result for the element you described. Compare it with the manufacturer's rating and your required service factor.
Formula and working
k = G·d^4 / (8·D^3·N)
- 1
Collect the inputs
Shear modulus = 11,500,000 psi; Wire diameter = 0.1 in; Mean coil diameter = 1 in; Active coils = 10
- 2
Apply the formula
k = G·d^4 / (8·D^3·N)
- 3
Result
Spring rate = 14.375 lb/in
Frequently asked questions
Symbols and assumptions
- G
- Shear modulus (psi)
- d
- Wire diameter (in)
- D
- Mean coil diameter (in)
- N
- Active coils
- • Standard textbook geometry and steady operating conditions are assumed; shock, misalignment and wear factors are not applied automatically.
- • Material and surface-finish allowances must be chosen by the user for their actual component.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • This is an educational estimate for learning and checking, not a design deliverable.
- • Real design must follow the governing code or standard for your jurisdiction and be reviewed and signed off by a qualified engineer.
- • Safety factors, load combinations and material certification are the responsibility of the designer, not of this page.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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