We love making clothes for the littles ones in our lives because most projects can be easily made in under an hour and the choice of patterns from Spoonflower is so much better than the options you will find pre-made at a store. With our free pattern, video and step-by-step instructions you will learn how to make a baby onesie. Using just one yard of your favorite knit fabric and our free pattern, you can sew two baby onsies in no time! Bonus: these make great baby shower gifts!

Baby Onesie Material

Pro tip: Try this pattern as a Fill-A-Yard® project! You can make two (any size) baby onsies with the vertical split yard template.

Steps To Make A Baby Onesie

All seam allowances are 5/8″ unless otherwise stated.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 1. Cut Out Your Pattern and Fabric

Start by cutting out and assembling your pattern pieces based on the size onesie you’re making. Pin the pattern pieces to your fabric and cut them out. Don’t forget to mark your notches! 

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 2. Attach the Neck and Leg Bands

Pin the neckbands and leg bands to the neckline and leg openings, matching the ends of the bands to the edges of the pattern pieces. Stretch the bands to fit along the curves and pin.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Sew the bands to the front and back pieces with a 1/4″ seam allowance. We’re using the Overlock stitch on our BERNINA B350, but using a serger or even a simple zig-zag stitch on your sewing machine are other great finishing options!

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Fold the band over the seam allowance and pin, taking care not to fold the seam allowance. Next, secure the band by topstitching along the seam, or “stitch in the ditch”, making sure to catch the loose end of the band from underneath. We’re using the SuperStretch stitch on our Bernina B350. However, using a Cover Stitch machine, a lightning bolt stitch (perfect for stretch fabrics) or simple zig-zag stitch will work as well! This will create a binding around the neckline and leg openings.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 3. Attach the Shoulders and Sleeves

With both right sides up and the necklines facing each other, place the Bodysuit Back over the Bodysuit Front, matching the shoulder notches, and pin in place.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog
Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Then, pin the sleeve section you just layered together to the arm opening, right sides together, matching all notches. Sew the sleeves to the arm openings with a 5/8″ seam allowance.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Next, fold the bottoms of the sleeves up 1/4″ and then another 1/4″. Stitch to secure the cuff.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 4. Attach the Onesie Sides

With right sides together, match the notches and underarm seams and pin in place. Stitch along the sides from the sleeve cuff to the leg bands. We’re using the Overlock stitch on our Bernina B350; but just like the previous finishing, you can use a serger or even a simple zig-zag stitch on your sewing machine.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 5. Add the Snaps

Finally, fold the bottom of the Bodysuit Front at the fold line. Secure by sewing a line 3/4″ from the fold. Attach the snaps to front and back pieces following the manufacturer’s instructions – Make sure to place your snaps on top of the marks you made in the first step.

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog

Step 6. Repeat Steps and Your Finished!

With the second 1/2 yard of fabric, repeat the steps to make the second baby onesie! This super cute and easy baby onesie pattern is ready for the little one in your life!

Make an Adorable DIY Onesie with This Free Pattern | Spoonflower Blog
Featured design: Bunny Races

Ready to DIY your next baby shower gift?

Frequently Asked Questions

How many yards of fabric do I need for a baby onesie?
To make one baby onesie, you only need a 1/2 yard of fabric. With Spoonflower’s Fill-A-Yard® vertical split template, you can choose designs printed on one yard of fabric for two unique onesies.
What are the measurements for a newborn onesie?
With our free pattern, you can make a baby onesie for a newborn and up to 18-months-old.
What kind of fabric is used for onesies?
We love using a soft, knit fabric like Modern Jersey, Organic Cotton Knit or Cotton Spandex Jersey.
Modern Jersey is 95% polyester, 5% spandex fabric with 2-way stretch and feels like the softest cotton, but with the added benefits of strong wash durability and wrinkle resistance. With a gentle drape and vibrant color, Modern Jersey has a cool feel and nice stretch recovery that suits a wide variety of garments. 
Organic Cotton Knit offers a medium-weight interlock construction that is extremely soft with a smooth hand. Featuring a natural 2-way stretch, this fabric has been a longtime favorite of makers who want playful designs on cozy apparel and accessories. Made with ecologically grown cotton, it has the perfect laid-back look and feel, making it a great choice for baby onesies, bibs and hats.
Cotton Spandex Jersey offers a 4-way stretch with a light to medium-weight durable knit construction of 93% cotton and 7% spandex. With great stretch recovery and natural breathability due to the cotton content, this fabric is best paired with lighter designs for softest feel and optimum color retention through washes.