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I’m so excited to share the baby shortall pattern and tutorial today!  I have loved making these little shortall’s for my son and hope you do to! They come together fairly quickly, and it’s so fun to see your t-shirt on your little one. I have reworked and updated the pattern and tutorial! Here’s the new tshirt romper tutorial and free patternOr buy the tshirt romper sewing kit!

FREE PATTERN: Baby Romper From Adult T-Shirt FREE PATTERN: Baby Romper From Adult T-Shirt
FREE PATTERN: Baby Romper From Adult T-Shirt

The pattern is for about a 6-12 month size. My baby is long and skinny with a smaller than average head, so you might have to adjust the pattern for your baby. If you have a chunky baby, add width to the sides of the body pattern. I’ll give you tips in the tutorial for adjustments.


What you need:
One adult t-shirt in any size, I used a male medium
sewing supplies* and sewing machine
FREE PATTERN in size 6-12 mos




(Go to my new tshirt romper tutorial for better instructions!)
1. Lay out your t-shirt and place the neckline of the pattern on the neckline of the shirt.

FREE PATTERN: Baby Romper From Adult T-Shirt FREE PATTERN: Baby Romper From Adult T-Shirt

2. Pin through both layers.

FREE PATTERN: Baby Romper From Adult T-Shirt

3. Cut out. At the neckline cut straight up then cut across into the neck hole at the top of the pattern. (If your neckline is really big, you might not need the whole neckline.

FREE PATTERN: Baby Romper From Adult T-Shirt FREE PATTERN: Baby Romper From Adult T-Shirt

4. Cut out the other pieces. When cutting out the sleeves, place the bottom on a hem so you don’t have to hem the sleeves. You should have one front and one back, four leg opening pieces, two sleeves, and one crotch piece.

FREE PATTERN: Baby Romper From Adult T-Shirt

5. Perfect the shoulders by angling in the edge so that the neckline ends in a point.

FREE PATTERN: Baby Romper From Adult T-Shirt FREE PATTERN: Baby Romper From Adult T-Shirt

6. With the back on the bottom right side facing down and the front lying on top facing down, overlap the points by 2″.
*This is where you can alter the pattern for head size and shoulder width. If your baby has a big head and wide shoulders, overlap less. If your baby has a small head and small shoulders, overlap more.

FREE PATTERN: Baby Romper From Adult T-Shirt

7. Find the center of the sleeve by folding in half.

FREE PATTERN: Baby Romper From Adult T-Shirt

8. Line up the center of the sleeve with the center of the 2″ right sides together.

FREE PATTERN: Baby Romper From Adult T-Shirt

9. Sew a zigzag at 1/4″.

FREE PATTERN: Baby Romper From Adult T-Shirt

This is what your neckline and shoulders should look like.

FREE PATTERN: Baby Romper From Adult T-Shirt


10. With right sides together line up the sleeve seams at the armpit. There will be a difference in length because of the size of the neckline. Also, the white arrow is point to the corner where the side should meet the sleeve. It doesn’t meet because I overlapped my neckline 2″. If you overlap yours less, I left room on the pattern so that you will have more room in the sides.

FREE PATTERN: Baby Romper From Adult T-Shirt

11. I drew a line from my sleeve seem to my hem and pinned. (It’s hard to see in the picture.) Sew with a zigzag at 1/4″ from sleeve hem, pivot under the sleeve and then sew down to the bottom.

FREE PATTERN: Baby Romper From Adult T-Shirt

12. Trim off excess.

FREE PATTERN: Baby Romper From Adult T-Shirt

13. Now lay down your shortall and cut off the excess so that the back to matches the front.

FREE PATTERN: Baby Romper From Adult T-Shirt

14. Fold the back and the football to find the center of each.

FREE PATTERN: Baby Romper From Adult T-Shirt

15. With right sides together, match the centers together.

FREE PATTERN: Baby Romper From Adult T-Shirt

16. Pin together. This is a little tricky because the two pieces are opposing curves. Sew at 1/4″.

FREE PATTERN: Baby Romper From Adult T-Shirt

This is what it should look like.

FREE PATTERN: Baby Romper From Adult T-Shirt

17. With right sides together sew with a straight stitch at 1/8″ on the outside curve. Do the same to the other two.

FREE PATTERN: Baby Romper From Adult T-Shirt

18. Turn right sides out.

FREE PATTERN: Baby Romper From Adult T-Shirt

19. With rights sides together pin the inside curve to the front inseam. Sew with a straight stitch at 1/8″.

FREE PATTERN: Baby Romper From Adult T-Shirt

20. Flip over to the inside and sew with a straight stitch at 1/2″ from the inseam.

FREE PATTERN: Baby Romper From Adult T-Shirt

This is what it should look like.

FREE PATTERN: Baby Romper From Adult T-Shirt

21. With right sides together pin the inside curve to the back inseam.

FREE PATTERN: Baby Romper From Adult T-Shirt
This is what the inseam should look like.
FREE PATTERN: Baby Romper From Adult T-Shirt

22. Pin up the bottom 5/8″ and sew with either a zigzag or a double needle.

FREE PATTERN: Baby Romper From Adult T-Shirt
FREE PATTERN: Baby Romper From Adult T-Shirt

23. Apply the closure of your choice. I did both snaps and buttons. I prefer buttons and buttonholes.

FREE PATTERN: Baby Romper From Adult T-Shirt

Put it on your cutie and enjoy upcoming summer!

FREE PATTERN: Baby Romper From Adult T-Shirt FREE PATTERN: Baby Romper From Adult T-Shirt
FREE PATTERN: Baby Romper From Adult T-Shirt

Author: Heather