Pattern adjustment for 3/4 length sleeves

I’m making a Noro jacket pattern and it calls for long sleeves and I’d like to make 3/4 length (or just below the elbow). How do I go about adjusting the sleeve pattern to do that? The pattern says to cast on 38 sts and working in garter st for 3", then working in st st 82 rows inc 1 st at each end of 5th and every foll 11th row = 54 sts. Continuing until sleeve measures 18", then the shaping of the sleeve top begins.

Thank you!

Since the pattern gives 18" as the length from wrist to underarm, you know how long that would be. Figure out at what measurement from the underarm you want your sleeves to hit, and then where that would be on the original pattern. Translate that measurement to row and you know how many incs will be done at that point, then use that number for your CO and work the garter stitch cuff. Though 3" is pretty long, you may only want 2". After that, continue the incs until you have 54 sts and work without increasing until the length you want.

Thank you so much for your detailed help. I agree that with the shortened sleeve length the 3" cuff would be too much and I’ll do 2" as you suggest.