As you open a Jalie pattern, you will notice that the pattern contains many sizes, all labeled with a letter (not a number). We do that for two reasons: because with kids and adults on the same sheet, a 6 could mean 6 years old or Women size 6 but mainly because we really want people to use the size that matches their body measurements, not the number they wear in other pattern brands or in ready to wear.
In most recent patterns, we mark the most important measurement in red. We recommend using the size that matches that body measurement and making adjustments if other measurements are bigger or smaller. For example, if you have a short torso, it is easier to shorten a garment that fits right in the width (armhole, neckline, etc) than the other way around.
Here is an example of the kids' section of the body measurements:
And adult measurements:
The JALIE size in the letter between F and GG. We included US and Euro sizing and approximate age in the charts in case you do not have the wearer available for measurements.
For those of you looking for S/M/L references, I recommend you check the ready-to-wear manufacturer's size chart to see in which Jalie size they fall to select the best one for your project. The steps being fairly small between sizes, going up or down by one size will never go from way-to-big to way-to-small. Our patterns are known for being true to size.
For more information regarding the back of the pattern, please visit our blog: http://jaliesewingpatterns.blogspot.com/2018/07/jalie-101-2-back-of-jalie-pattern.html
For information more specific to leotards/swimsuits/skating dresses, check out this article on our blog: https://jalie.com/blog/tutorial-sizing/