Our Spring Rate Conversion Calculator Tool is designed for reference purposes only in order to help determine the approximate rate of existing unmarked helical round wire compression coil springs. There are many variables which are not represented in these calculations, therefore it should just be used as a reference for conversion. Results are rounded to the nearest whole number.
Enter a number into any field below to see results.
Spring rates refer to the stiffness of a suspension spring, typically measured in pounds per inch (lb/in) or newtons per millimeter (N/mm). This measurement tells you how much force is needed to compress the spring by a certain amount. For example, a spring with a rate of 500 lb/in requires 500 pounds of force to compress it by one inch.
In suspension tuning, spring rate is one of the most important factors that affects a vehicle’s handling, ride comfort, and performance. It determines how much the suspension compresses under load—from the vehicle’s own weight, passengers, cargo, and driving forces like cornering, braking, or acceleration.
Choosing the correct spring rate is all about balancing performance and comfort. For street-driven cars, a moderate spring rate can offer the best compromise. For track or motorsports applications, a higher spring rate is often preferred to keep the car planted and responsive.
Your ideal spring rate depends on factors like:
Need to convert between kg/mm and lb/in? Use our Spring Rate Conversion Tool right here on this page to make accurate adjustments for your setup.
