How to add sleeves to a onesie or other small tyke's shirt (and make it look layered)

It’s beautiful weather in these parts. Saturday dawned clear and beautiful, we had expected rain and the skies were clear, which made me oh so happy. Cuppycake has all these precious onesies that she hasn’t outgrown yet, but that have no sleeves. Unfortunately, the weather is really too cool for her to be wearing short sleeve onesies, and putting a sweater on her to go to the car is a pain. Especially when it’s cool enough to wear a long-sleeve shirt and a hat but too warm for a sweater. So. Pappa Starbucks has been bugging me to go buy some onesies for her that have sleeves, just so we can put her in jeans and a onesie again, or snuggly leggings and a onesie- but oh no. I’m too cheap way too creative for that, so I dug out the sewing machine and put sleeves on her Eensie. Teensie. Onesies.
It was really much much easier than I expected, although I really haven’t finished them all yet since our professors are in that phase where they assign six papers a week and 800 pages of reading per class period, so we’re struggling to keep our assignment level caught up enough that we can actually use the dinner table for, well, dinner.
Here’s how to put sleeves on a onesie, or other shirt. The sizes I added them to are 3-6 months, and although I don’t have measurements for other sizes, all you need to do is:
Measure the length of you child’s arm from where their current sleeve ends to their wrist. I used short sleeve onesies, and for 3-6 months, this length was 6 ½ inches long,and don't forget I used the seam at the bottom for the cuff and 5 1/2 inches wide .



The fabric I chose was some of my old (maternity) tee shirts in plain colors that I knew would correspond with her pant selection so that there wouldn’t be too much ‘funkyness’ in her closet. I've tried it with several fabrics, and old tee shirts are by far the softest, but you could use anything.


Next, pin your sleeve together, wrong side out, like I did, and sew along the top. This will be the bottom of the sleeve once you’re done. I sewed my sleeves twice, just because cuppycake LOVES to chew on them. And I didn’t want to have to regret putting them on there later. Once you’ve made a sleeve, turn it right side out, and then comes the hard part. I’m not a big pin user, but. These onesies are tiny, and if you don’t pin these sleeves to the onesie, then the chances are that you will mess up you’re going to get really frustrated.




Yes, my camera stinks, and the flash is totally killing this photo. But. What you need to do is make sure that the seam of your sleeve is lined up with the seam of the smaller sleeve: both are on the bottom. You are going to pin, pin, pin like crazy because these guys ares so very small.

I always sew from the outside, and I either chose a thread that matches the onesie, or that contrasts with cuteness. I've done one black onesie with black sleeves and black thread and it was SO easy. On all the others, I've used white thread and very tiny stitches so it will hold well, and it has worked great.


This way, I can follow the seam that's already on the onesie sleeve: because I want it to look layered. If you want to make the sleeve look like a continuation, that's a whole different post.
And then, you sew. I sew from the outside of the onesie to make sure I am following the pre-existing seam. You can sew from the inside if you want. The nice thing about these onesies is that theY are forgiving! I've made a few mistakes, but in general, they just look all the cuter for it.

Have fun!!