Size Inclusion & Kids: the Problem with Sleeves
Updated: Feb 16, 2021
"Great pattern, but I had to knit 36 extra rows to make the sleeves long enough for my daughter!"
I've come to expect comments on sleeve length. The first time, I panicked. Was it my size chart? The math? My sleeves worked perfectly! But then another tester finished the same sweater.
"I love this sweater but the sleeves are way too long! I'll have to cuff these to make them work."
What's up with sleeves and kids?
Grading for adults assumes that everyone, no matter their chest circumference, has a frame the exact same size. My size chart is based on Ysolda Teague's, and every single size has the same exact arm length. This consistency is good for knitters - I think we all know whether we have long arms or short arms, and we have learned to adjust accordingly.
But while adult sizes have just one variable, each children's size also varies for expected height. If children's patterns were size-inclusive we would grade multiple chest circumferences for each height. There might be 6 different size 4's! But we don't do things that way. And because children grow into new sizes all the time, often filling out and then stretching up, they may not even stay the same circumference-to-height ratio, so we can't rely on them having a longer or shorter arm for their age-size. Not helpful!
This all means that a child who is average height but slender for age may size down in the chest, and have inches of arms showing. A child with an average chest circumference but who is tall for their age will also need a longer sleeve. And on the other hand, a child that sizes up for chest circumference or falls lower on the height percentiles may have puddles of sleeve stacking on top of their wrists.
What to do about it?
The best way to get a good fit for sleeve length is to compare the pattern's schematic to your child's arm length. Once you know the difference, you can think about where to make adjustments.
If the sleeve is knit straight, you have it easy and can just knit more or fewer rows. If the sleeve is shaped though, things are trickier. If you are adding just a few rows, you're probably fine to slip them in right before the underarm. After that, you're going to get to do a little math.
For Little Sunup (coming later this month!), my model's arms are 3" longer than the arm length predicted by my size chart for her chest circumference. To show knitters what the sleeves will look like when the sleeves fit I opted to modify the sleeve length for the sample. I multiplied the number of inches (3) by the row gauge (7.5 sts/inch) to arrive at an extra 22.5 rows, which I rounded down to 22 so I could add an even number of rows. I added two rows right under the underarm, leaving 20 to distribute into the shaping. The pattern calls for working 56 rows, decreasing every 8th row seven times. Instead, I decreased every 12th row three times and every 10th row four times, alternating to keep the line straight.

Photography: Anna-Lisa Miller @AHiddenPurl
TL;DR
1. Kid's arms will rarely match the pattern exactly, and sometimes will be wildly off!
2. Only add or subtract a few rows between the shaping and the underarm, the portion worked straight should be pretty close to 1-2".
3. Calculate the number of rows you need to add or subtract based on gauge and redistribute into the shaping provided.
Feel free to let me know if this helps, or if you have any additional thoughts - especially on how the movement for size inclusivity could do a better job of including kids!