Zipper (approximately 4” longer than your laptop)
Measure your laptop, wrapping your tape measure all the way around.
Mine measures 18.5” X 24.5”. (Yes, it’s tiny.)
Split both of those measurements in half. In my example, that would be 9.25” X 12.25”. Add 1.25” to both of those measurements. In my example that’s 10.5” X 13.5”. We’re finished with the math. Cut 2 pieces from your outer fabric this size. Cut 2 pieces from your lining fabric this size. Cut 2 pieces of fusible fleece this size. I then trimmed 1/2” off all around my fusible fleece because I didn’t want the bulk in my seams.
Cut a strip of fabric 3.5” wide and then press under 1/4” on the top and bottom edges.
Iron your fusible fleece to the wrong sides of both pieces of outer fabric, following the manufacturer’s instructions.
Take your zipper and place it face down and centered along the top edge of your front piece. You should have excess zipper on both ends.
Here’s what you’ve got now…nice neat zipper and ugly unfinished seams everywhere else.
Reach up between the exterior layers and undo the zipper a few inches (big enough to fit your hand through and reach to undo the zipper the rest of the way later).
You’re going to sew ONLY on the exterior pieces. Fold, pull, and otherwise maneuver the lining pieces out of the way. You’ll be sewing from one end of the zipper to the other.
Repeat with the lining pieces, BUT leave a 4-5” hole in the bottom (again, big enough to fit your hand through).