Free Spring Calculator for Compression, Extension and Torsion Springs
Lee Spring's free spring calculator helps you check the performance of compression, extension and torsion springs before you buy or build. Select a spring type, enter the dimensions you know, and review calculated values such as spring rate, force, stress and travel. When your design looks right, send it to our engineering team for a custom quote or find a stock spring from our extensive selection.
Choose your calculator
Compression Spring Calculator
For springs that resist an axial load. Enter wire diameter, outside diameter, free length and total coils.
Calculates
- Spring rate, index and active coils
- Solid height and deflection to solid
- Force and stress at solid height
- Pitch, helix angle, mean and inside diameter
Extension Spring Calculator
For springs that resist a pulling load. Enter wire diameter, outside diameter, body length, coil count and end type
Calculates
- Spring rate and initial tension
- Free length inside hooks
- Force and stress at extended length
- Maximum safe travel
Torsion Spring Calculator
For springs that resist rotation. Enter wire diameter, outside diameter, leg lengths, coil count and wind direction
Calculates
- Rate per degree of deflection
- Torque at working angle
- Bending stress
- Body length and diameter change under load
From calculation to quote
Submit a quote request using the inputs and results from the spring calculator. Our experienced engineering team will review your specifications and provide a detailed, personalised quotation.
25,000+ stock springs
If a stock part fits your design, you can order it today from the Lee Spring catalogue.
Engineering support since 1918
Talk to an engineer about materials, finishes, tolerances and production volumes.
How the spring calculator works
Choose your spring type.
Select a compression, extension or torsion spring calculator.
Enter your known dimensions.
Add measurements such as wire diameter, outside diameter, length and coil count, plus end type or leg details where they apply.
Review the calculated performance.
See spring rate, force or torque, stress, travel and other values for your design.
Request a quote or find a stock spring.
Send your inputs and results to our engineering team for a custom quotation, or order a matching part from the Lee Spring catalogue.
Spring terms the calculator uses
- Spring rate
- The force needed to deflect a compression or extension spring one unit of length, shown in N/mm or lb/in. For torsion springs, rate is the torque needed per degree of rotation.
- Spring index
- Mean coil diameter divided by wire diameter. It indicates how easy the spring is to manufacture.
- Active coils
- The coils that deflect under load.
- Solid height
- The length of a compression spring when it is compressed until all coils touch.
- Initial tension
- The internal force that holds the coils of an extension spring together. The load must exceed it before the spring begins to extend.
- Torque
- The rotational force a torsion spring produces at a given angle of deflection.
- Stress
- The stress in the wire under load, used to check that the spring will not take a permanent set.
Want more definitions? Read the Technical Glossary.