How to measure stretch of knit fabric

AKA "pick-a-knit" rule.
I recently googled how to measure knit stretch and every configuration there of in hopes of find some info on how to accuratly measure the percent of stretch of knit fabric to insure that our customers are getting the most accurate product info. I could not find the info anywhere. By some good will of the internets gods, I stumbled across a forum discussing the "Pick-a-Knit" rule which guided me the rest of my way. Here is a simplifed location to get your info to determine the stretch of your knits.

1) Determine which direction is the stretchiest, this is the direction you want to measure. Typically, across grain is the stretchiest, but if I say it is a fact, there will be an exception. So test to be sure.

2) Grab a ruler or measuring tape and hold it on your knit in the direction of stretch. pinch the fabric at the Zero mark and at the 4'' mark and pull. Pull till you feel resistance, if you pull farther than that you are distorting the fabric. Make a note at where the resistance starts. you can use any spanse of measurement, 4'' is just a decent base measurement to use to make sure you are getting a true stretch

If you were able to pull the fabric 1'', 1''/4''=.25, than you have 25% of stretch. 2'' is 2''/4''=.5, 50% stretch.
You can use this equation:

• base number (we used 4'' above): Y
• inches of stretch: X
  
  
  
  
  
  
  

I really hope this helps and that I explained it in a way that is easily understood. If you have any questions, please let me know
Happy Sewing,
Tara