Easy Spring Rate Conversion

We frequently convert spring rates from US to metric units, or metric to US. Here is a quick conversion chart and some easy math to do the job for you.

• To convert lbs/in to kg/mm, divide by 56.
• To convert kg/mm to lbs/inch, multiply by 56.
• It’s quick and easy to remember!

Lbs/ inch              Kg/mm

200                         3.6

250                         4.5

300                         5.4

350                         6.3

400                         7.2

450                         8.1

500                         9.0

550                         9.8
600                         10.7

650                         11.6

700                         12.5

750                         13.4

800                         14.3

850                         15.2

900                         16.1

950                         17.0

1000                       17.9

1050                       18.8

1100                       19.7

1150                       20.6

1200                       21.5