Success with Sleeve Length
Sorting out sleeves
It’s painful to knit a sweater, put it on, and have regrets about the sleeve length.
Sure, if you’re knitting top-down in the round you can try on as you go, but for that strategy to work you need to know for sure that your working gauge (your gauge before blocking) matches your blocked gauge, or you might still be unpleasantly surprised.
If you’re knitting another construction, or if you want to guarantee a nice shaping line, it pays to evaluate sleeve length before casting on.
What determines sleeve length?
For your sweater’s sleeves to be accurate, two measurements need to line up: your sweater’s back neck to cuff, and your body’s back neck to wrist.

Your body measurements
If at all possible, have someone help you with taking your measurements. Relaxed and with your arms down at your side, measure from the very tip of one shoulder to the other, across the back. Then, measure from the same tip down to where you want your cuff to hit your wrist. One-half of your shoulder-to-shoulder width + your arm length is the critical measurement we’re looking for.
Evaluate sweater measurements
Yoke sweaters: ½ back neck plus sleeve length
Raglan: ½ back neck plus raglan depth plus sleeve length. Raglan depth is the number of rows worked from the cast on to the underarm split (a vertical line) and is not the diagonal length of the raglan shaping.
Set in: ½ of the body width (typically front chest width) plus sleeve length.
Dropped shoulder: ½ of the body width, plus sleeve length.
