Bright Neon Baby Onesie from a T-Shirt

I’ve seen onesies made using a t-shirt before. But, this method is a little diffeent. With this method, you get to keep the neckline ribbing in place. This is easy, and makes for a much nicer “finished” neckline for those that are newer to sewing.

This one is done in neon in celebration of Neon Week over at Madigan Made and the neon challenge at Refashion files. Back when I wore neon in the 80’s I had no clue that it would ever come back in style. Though, let’s be honest… it never really was stylish to wear pink neon sandals with my green girl scout socks. Ummm… not that I ever did that. often. ish.

Okay! On to today’s tutorial… if you want to convert a tee to a onesie with this awesome method I cooked up, start by collecting your supplies…

One adult-size shirt
Onesie (for tracing a pattern)
Freezer paper
3 snaps
Fabric Paint (optional)

I started by tracing a onesie on freezer paper, drawing the major outline darker, and adding seam allowance. I folded the freezer paper in half to make sure the pattern was symmetrical, then cut it out.

I ironed the front to the front of the t-shirt, lining up the pattern neckline to the shirt neckline, and cut out. I repeated this with the back pattern piece as well.

Then, I lined up the neckline pieces before pulling off the freezer paper.

I pinned everything in place. I might have gone a little overboard with the pins. Just a little.

I traced the sleves, cut them out with the sleve hem on the existing shirt hem (to avoid more hemming), and then pinned the sleeve in place before sewing.

After stitching the sleeves on using the stretch stitch on my sewing machine, I pinned down the side of the onesie, from the sleeve all the way down to the bottom. Then I stitched this, again using the stretch stitch.

Now comes the only tricky part of making a onesie this way. The neckline and sleeves are perfect, but the crotch needs to be finished. So, I cut a 3″ strip from the bottom of the shirt, and ironed in half, then ironed the two sides in to the fold to make “bias tape” that isn’t really on the bias.

I pinned it in place all the way around. I don’t think it is possible to have too many pins here. 

I stitched this in place with two rows of stitching, going slowly and carefully, making adjustments as needed to make sure that both sides of the binding got caught in the stitches.

I stitched 3 snaps in place across the bottom, and the onesie was done!

For fun, I added a little paint… because this onesie wasn’t bright enough already!

Though, adding the paint would be a lot easier if I had a Simply Screen. Which I’m trying to win by entering this onesie in the Neon challenge over at Refashion Files. There is still time for you to create your own Neon refashion and link it up on July 23rd!



  1. LOVE it, Carolina! I’m ‘sew’ impressed. The color is fun and the lightbulb is perfect.

  2. Yahoo! I ‘saw’ this on Pinterest first Carolina and had to come check it out. Love it! <3

  3. I love it!! How do you find the time to be so creative and awesome with your two LO??
    You are amazing!!!

  4. Very Cute!! – Not sure I would have the patience to do it, but your’s turned out great!!

  5. I love this idea. I saw something similar on pinterest. Love the idea of recycling old tshirts!

  6. I’m seriously looking at this and thinking WOW…a onesie from an old t-shirt?!? Such a creative idea and so resourceful too.

  7. This is so cute. How clever! I love it.

  8. I’m making this from an old bandshirt… Coming along very nicely =) Thanks for sharing!

  9. The t-shirt in the picture is a Youth size, but the instructions say to use an adult size. Does it take the adult size to get the length you need on the neckline? Or what’s the reasoning for the adult size? And would that be even a Small adult size? or does it need to be a larger size?

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