Sewing a Baby Sleep Sack for 1 to 4 Months: Pattern and Tutorial
A step-by-step tutorial for sewing a baby sleep sack: print and tape together the pattern (or draft it yourself from a grid diagram), cut the bib, back, and bag pieces, sew the lining to the batting and quilt it, gather the top of the bag, sew the bib to the front, insert a zipper into the side seam, join the outer fabric to the lining, and bind the raw edges with bias tape.
Intermediate2 hr 30 minFree
Translated
Things you will learn
The sleep sack fits babies up to 3-4 months old and fastens at the side with a zipper sewn into the side seam; the straps have two button or snap fasteners.
Print the pattern pieces on A4 paper at 100% scale and tape them together in pairs — sheet number 2 isn't needed, since it's blank. If you don't have a printer, you can draft the pattern yourself from a grid diagram with 5x5 cm squares — the seam allowances are already included in the pattern.
For the outer fabric (cotton is best) you'll need 100x80 cm, and for the zipper, 90 cm; the number of fabric layers depends on the season — one or two layers of fabric are enough for summer, while winter calls for batting.
The bib and back pieces are cut separately from the bag; sew the lining to the batting and quilt it so the batting doesn't clump together after washing.
Sew the zipper to the outer fabric at the side seam, then fold it inward and stitch the lining over it so the zipper tape's raw edges end up on the inside once turned right side out; bind the raw edges around the armholes, straps, and neckline with bias tape.
What you'll get
A baby sleep sack with a side zipper, a lining (with batting for warmth if needed), strap fasteners, and raw edges finished with bias tape.
Materials and tools
Materials
Outer fabric (cotton), 100x80 cm, cotton is preferred; the number of layers depends on the season
Lining fabric (calico or jersey)
Thin batting for warmth, needed for the winter version of the sack
Zipper, 90 cm, sewn into the side seam of the sack
Bias tape, used to bind the raw edges around the armholes, straps, and neckline
Two buttons or snaps, used as fasteners on the sack's straps
Tools
Ready-made paper pattern, printed on A4 paper at 100% scale and taped together in pairs, or drafted yourself from a grid diagram
Scissors, for cutting the pattern pieces and fabric
Thread, for the machine seams
Pins, for pinning the pieces together before sewing
Sewing machine, for all the main seams, the quilting, and inserting the zipper
Preparation
Gather your materials
Gather the outer fabric (cotton is preferred, 100x80 cm), lining fabric (calico or jersey), thin batting for warmth, a 90 cm zipper, bias tape, a ready-made pattern, scissors, thread, pins, and a sewing machine.
Print and tape together the pattern
Print the pattern sheets on A4 paper at 100% scale and tape the finished paper pattern pieces together in pairs (sheet number 2 isn't needed — it's blank). If you can't print a ready-made pattern, draft it yourself from the diagram, where each grid square equals 5x5 cm; the seam allowances are already included in the pattern.
Cut the pieces
The bib and back pieces are cut separately from the main bag; the number of fabric layers depends on the season you'll use the sack in.
Decide how many layers of fabric to use
The number of layers in the sack depends on the season you plan to use it in. One or two layers of fabric are enough for summer, while winter calls for batting.
Cut the bib and back pieces
Cut the bib and back pieces separately from the bag.
Pattern sheet with the main bag piece
Sew and quilt the lining
The lining is joined to the batting and quilted so the batting doesn't clump together after washing.
Sew the lining to the batting
Sew the lining to the batting.
Quilt the layers
Quilt the layers together — this keeps the batting from clumping up after washing.
Gather the top of the bag and sew on the bib
The top of the bag is gathered and joined to the bib and back along the side seams up to where the zipper begins.
Gather the top of the bag
Gather the top of the bag a little at a time, until the length of the top edge is 35 cm and matches the bib and back.
Sew the bib to the front of the bag
Sew the bib to the front of the bag along the side seams, up to where the zipper begins (the zipper's placement is marked in red on the diagram).
Grid diagram for drafting the pattern
Insert the zipper
The zipper is sewn into the outer fabric's side seam, and the lining is stitched down so the zipper tape's raw edges end up on the inside.
Sew the zipper to the outer fabric
Sew the zipper to the outer fabric of the sack, then fold it inward and stitch the lining over it, so the zipper tape's raw edges end up on the inside once the sack is turned right side out.
Turn the sack right side out and press the seam allowances
Turn the sack right side out and steam-press the seam allowances flat so they don't show through the fabric.
Join the pieces and bind the edges
The final step is joining the outer fabric to the lining around the armholes, straps, and neckline, and binding the raw edges with bias tape.
Baste the pieces together and bind the edges with bias tape
Baste the outer fabric and lining pieces together around the armholes, straps, and neckline, then bind the raw edges with bias tape.
The finished sleep sack
Add decoration if you like
If you like, you can decorate the sack with an appliqué, lace, or embroidery.
Finish and variations
Finish
Decorate the sack if you like
The base of the sleep sack is now finished; if you like, you can decorate it with an appliqué, lace, or embroidery.
Intermediate2 hr 30 minFree
