Pattern Hack – Lilium Laptop Bag

Sew Sweetness Lilium Bag pattern hack

This is a pattern hack of the Sew Sweetness Lilium Laptop Bag sewing pattern. The modification is to widen the bag for a diaper bag! While this tutorial is free, you’ll need to pick up the Lilium Laptop Bag pattern in order to complete the rest of the bag.

DEFINITION – Pattern Hack [pat-ern hack]: to modify or write a sewing pattern in a skillful or clever way.

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This post is part of an ongoing series from my Pattern Hack Posse, and was written by Cyndi.  You can find her at The Nosy Pepper and on Instagram!

 I love the style of messenger bags as diaper bags because I can just flip the top over and not deal with fussy zippers or buttons while carrying a kiddo (and who knows what else around).  I have been swooning over the Lilium Laptop Bag for a while, with the shape of the flap and all the interior pockets but I needed it to be a bit wider than the pattern allows. Of course every diaper bag also needs some side pockets to stash sippy cups, bottles and whatever else those littles hand you.


To convert this into a diaper bag, I increased the width of the bag through the side/bottom panel, added a back slip pocket and elasticized side pockets. Pockets are a parent’s BFF! I will walk you through each step of the process, so if you haven’t already get your copy of the Lilium Laptop Bag! We will be working from the LARGE sized laptop bag.

For starters, this will require some additional fabric and notions:

  • 16 inches of ½” knit elastic, cut into (2) 8” pieces
  • An additional ½ yard of fabric for the exterior and a ½ yard of fabric for the interior (I still had plenty left over though, so you may get away with a bit less if you aren’t using a directional print).
  • If you choose to use vinyl you will need 1/3 for the accents and strap. Even in you choose to use the vinyl you will still need at least ¼ yard of the accent fabric to make the side pockets
  • An additional half yard of shape flex, but you may be able to piece it from left overs
  • Safety pin to feed the elastic through the pocket pieces


During the cutting you will make the follow changes for the large bag:

From the exterior fabric:

  • Cut 1 exterior side/ bottom panel 42” x 8” *** this is different than it is listed in the pattern**
  • Add 4 inches to the top of the flap and accent pieces (I did this by taping an additional piece of paper and cutting it to size.
  • Cut 2 divider pocket pieces from the pattern piece

From the accent fabric:

  • Cut 4 side pocket pieces 16”x8”

From the lining fabric:

  • Cut 2 side/bottom panels 42” x 4 ½”

From the shape flex:

  • Cut 2 pieces from the divider pocket piece
  • Increase the size of the exterior side/bottom panel and the interior side/bottom panel to the new widths.

**Cut the remaining pattern pieces as indicated in the pattern directions, since we are not using this to carry our laptops, we can omit the ½” foam and the ½ yard of cheap fabric***


Step 1) Making the side pockets.

Now that the pieces have been cut, we need to turn them into a trapezoid. We do this by folding our  16” x 8” piece in half and making a dot that is 4” down from the non folded side and then drawing a line between that dot and the top edge of the folded edge as shown below:

lilium1Cut along the line that you drew, as indicated in the dotted line above.  Your pocket will now look like this:

Take 2 side pocket pieces and pin or clip wrong sides together. Sew ¼” away from the TOP long edge and the BOTTOM short edge as indicated in the photo:


Now the tube you just made inside out, and stop stitch along the TOP long edge using a ⅛” seam allowance, then stitch ⅝” . This will create a casing that we will feed our elastic through. Pin one end of the elastic and using the closed safety pin, feed this through the casing you created. Once you pull the end of the elastic not attached to the pin to the edge, baste this down to keep it from pulling all the way through. Continue feeding the elastic through until you pull the end with the pin completely through. Now baste this side down as well. It will look like this:


We are now going to attach our pockets to the side panel of the bag. Measure and draw a horizontal line 8” down from the top edge of the side/bottom exterior panel. Align the bottom edge of this pocket directly above this line. Pin or clip (clips are much easier here) this pocket in place.


Repeat this with the second pocket and panel and set aside.

Make the back pocket:

  • Take the two pieces you cut from the exterior fabric using the divided pocket pattern piece. Sew these using the directions from step 50-51 in the pattern to create your back pocket.

In steps 15-16 in the pattern, we will  be attaching the accent pieces to the back pocket, as shown below:


The exterior back panel will look like this:

lilium7 Finish your bag as per the pattern instructions, and you will have successfully transformed your laptop bag pattern into a diaper bag!

Sew Sweetness Lilium Laptop Bag pattern hack

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