Save yourself some work, and fold the fabric with the right sides facing in. If you don’t have a onesie, find some pants and a shirt that fit your baby. Place them on the fabric, with the waistband and shirt hem touching. [2] X Research source
You are cutting out a crescent shape. This way, you won’t be widening the collar. If you widen the collar, it won’t match up with the back piece.
Skip this step if you are making a long-legged onesie.
If you are making a legless onesie, measure the entire front crotch flap, including the leg holes. Do the same for the back piece. If you are making a long-legged onesie, you only need measure 1 leg cuff and cut 4 pieces of ribbing for the leg cuff. You’ll be hemming the inseam instead.
You will need 1 piece for each measurement that you took.
This step is similar to folding bias tape.
Use a thread color that matches the fabric. Backstitch when you start and finish sewing. Do not fold the strips down or top stitch them yet. You’ll do this last.
Use a thread color that matches the onesie fabric. Backstitch when you start and finish sewing. Use sewing pins to hold the fabric together if you have to, but remember to take them out when you are done. You are sewing across the seam created by the collar and ribbing. Fold this seam towards the ribbing as you sew.
Cut V-shaped notches into the curved edges of the armholes when you are done. Be careful not to cut through the stitching.
Use sewing pins to hold the onesie together if you need to, but remember to take them out. Once again, fold the seam created by the ribbing and the sleeves/legs towards the ribbing.
If your ribbing is a different color from the rest of the fabric, match the thread color to the ribbing.
How many snaps you use on a long-legged onesie depends on how long the legs are. Space them every 2 inches (5. 1 cm) or so.
A snap tape is a strip of twill ribbon with snaps already attached.
