How to Make a Baby Romper from a T Shirt

Get a youth-sized t-shirt and a pre-made romper (aka a "onesie").

Turn your t-shirt inside out. Fold both the t-shirt and the romper in half and lay the romper on top of the shirt, lining them up at the fold. Trace.See how the crotch on the romper puffs up because it's in a shorts shape? Ignore that. You'll have to fudge a bit for the bottom part. Use the image as a guide.You should narrow the sleeves (or take them off altogether, up to you). So basically you're cutting a chunk out of the armpit and then letting it widen for the legs.

where the orange line is; click to enlarge image.]]Sew on the armpit line only. Don't close the leg area.

Unfold and cut just outside of the line you just sewed. Go ahead and cut your bottom line too, just make sure you leave enough to hem or you'll get an underwear shape.

Fold it over and trace what you've just cut onto the other side. Don't let your cat help, he doesn't have thumbs.

Sew the armpit line on that side and cut.

Attach your closure. If you use snaps, reinforce your fabric with something that doesn't stretch so they hold up better. Make sure your closures are so that the flaps point toward each other when you go to close it. So both sides should be facing up when laid flat.

Stop here if you don't mind a homemade appearance. Otherwise, you'll want to hem. Cut that little diagonal slit between the crotch flap and the rest of the leg so your corners don't bunch.

Turn the finished romper right side out .