How to Sew a Cardigan Onesie

How adorable is this cardigan onesie? We fell in love with it too the first time we saw it on Feather’s Flights. In fact, there are a bunch of great tutorials for baby boys there, like the Little Boy Tie and Baby Shortalls from a T-shirt. The Men’s Shirt Baby Romper looks just like a little gentleman’s button-down dress shirt.

Now, let’s check out the full How to Sew a Cardigan Onesie tutorial…

How to Sew a Cardigan Onesie

Hey there! I’m Heather *Feather* from Feathers Flights where I blog about all my “flights” in sewing. I love sewing and sharing easy projects to show the sewing isn’t scary! This cardigan onesie is a fun refashion for a long-sleeved onesie. The best part about these cardigan onesie is that they show off baby legs!

Long or short sleeved onesie- (I think the short sleeved ones look best on girls.)
RIBBING (make your life easier by using ribbing and not regular knit!)
Sewing machine, pins, scissors, thread

1. If your onesie has crossover shoulders, find where the crossover lays flat and pin two layers together.
2. Either zigzag or double needle the two layers together.

3. Measure across the front of the onesie and mark the center all the way down. At the bottom slant to one side between two of the snaps.

4. Cut on the line.
5. Draw from shoulders to parallel with the armpits.
6. Cut on lines up around the neckline so that you cut off the neck band.

*This is perfect if there’s a small picture, phrase, or stain near the neckline that you want to get rid of.

7. Measure the whole cut edge. Take the measurement and multiply by .75. Add 1/4″ seam allowance. This is the length of the front band. I wanted my band to be 3/4″ tall, so double that amount and add 1/4″ seam allowance. Make sure the stretch goes with the long sides.
8. Sew ends at 1/4″.
9. Turn right side out and poke out corners.

10. Find the center of the band and then the center of each side, so you divide the band into four sections. Use the same method to divide the cut edge of the onesie into four sections. Match pins.

12. Stretch each section and pin so the excess is distributed evenly.
13. Stretch while zigzagging at 1/4″.

14. Zigzag the edges of the snap facing to prevent fraying.

15. With your machine set on to a straight stitch, stretch and sew the seam allowance towards the onesie. Sew at 1/8″. Careful when going over the shoulders.

16. Snap the snaps together overlapping the two sides.

17. Pin the two layers together and sew together.

18. Pin two layers of the front band together at three or four places. Sew buttons on at each pin.

19. Cut off sleeve hems. Measure length.
20. Take the measurement and multiply by .75. Add 1/4″ seam allowance. Use the same height as the front band.
21. Sew short edges to make a tube. Fold in half with right sides out.

22. Sew band to each sleeve end at 1/4″ stretching to fit.
23. With a straight stitch, stretch and sew the seam allowance towards the sleeve at 1/8″.

These baby boys are off to college in their new cardigan onesies.

It’s great for playtime!




I love these and they cost so much on etsy I might just give it a try!! I’ve not sewn much and have no idea what ribbing is?? Where can I find it?


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