Sewing tutorial

Square Bottomed Shopping Bag

Shopping bags often have rectangular bottoms and a prismatic shape. This is great if the items you want to place inside the bag also have a rectangular bottom or are smaller than the bottom of the bag. I discovered a limitation of my rectangular bottomed shopping bags; larger square items don’t sit flat inside them. This is a square bottomed shopping bag tutorial.


All of my grocery bags and shopping bags are either have rectangular bottoms or don’t have boxed corner. Sometimes I find it difficult to pack larger rectangular items in these bags as they don’t lay flat in the bottom of my bags. Pizza boxes and square egg cartons are especially problematic. Pizza toppings can slide off the pizza and eggs can get cracked or broken. This became more of an issue when I decided to buy all my eggs in square cartons. The carton often looks like this by the time I get home.

Square carton of eggs carried in a rectangular bag

I decided to sew a square bottomed shopping bag so that I could pack my square egg cartons flat. This tutorial shows you how to make a 12.6” tall by 12.2” wide by 11.8” deep (32 cm tall by 31 cm wide by 30 cm deep) square bottomed shopping bag. This is a beginner tutorial.

This Sewn By Tanya project is for personal use.

  • 1/2 yard quilting weight cotton or light canvas (may need more if matching directional prints)
  • fabric marking pens/chalks
  • scissors or rotary cutter
  • ruler
  • iron & ironing board
  • sewing machine
Seam allowance: 1/4” (0.6 cm)
Step 1 Gather Materials

For this project you will need a some quilting weight cotton, light canvas or medium-heavy weight home decor fabric.

Cut the following:

  • one, 46” x 4” quilting weight cotton strip for the straps
  • one, 41” x 13” quilting weight cotton piece for main panel (front, bottom and back)
  • two, 14” x 13” quilting weight cotton pieces for side panels
Materials for square bottomed shopping bag
Step 2 Hem

Place your main panel right-side down (wrong-side up) on your work surface. Mark the mid-points of the long edges. Fold the 13” edges 1/4”, pin and press.

Single fold hem

Fold the 13” edges another 0.75”, pin and press. Stitch 1/8” from the double-fold.

Double fold hem


Stitch 1/8” from the single fold (top edge).

Top-stitch upper edge


The hems of your main panel will be along the top edges at the front and back of your bag. Mark the midpoint of each hem on the right-side and wrong-side of your main panel.

Fold, pin, press and sew one 13” edge of each side panel. Mark the midpoint of the other 13” edge of each side panel. The hems of your side panels will be at the top of your finished bag.

Step 3 Assemble Body

Place your main panel and two side panels wrong-side up on your work surface. Line up the center marks on the main panel with the center marks along the bottom edges of each side panel.

Align center marks

Pin the side panels to the main panel at these marks with right-sides together. Pin the bottom edges of the side panels to the main panel then the sides of the side panels to the main panel. An 1/8” snip  in the main panel where it meets the corners of the side panel may be needed. The hems will all line up at the top.

Sew the side panels to the main panel using a 1/4” seam allowance.

Sew side panels to man panel

Turn your bag right-side out. Pin the seams closed then press and top stitch 1/4” from the first seam. This will hide your raw edges.

Finish seams
Step 4 Make Straps

Cut your 46” by 4” strap piece into two 23” by 4” strap pieces. Fold the short end of each strap over 1/2” and press.

Fold-over strap ends

Fold the straps in half to create a 2” wide strip. Press then open the strip. Fold the raw edges of the strips in so that they meet at the center along the pressed fold. Press again.

1″ wide strap

Top stitch 1/8” from the double-folded edge of the straps then 1/8” from the single-folded edge.

Top-stitch straps

You now have two, 22” long by 1” wide straps.

Step 5 Attach Straps

Measure 2.25” from the midpoint of each main panel hem. Measure 2” down from the top of the hem at each of these marks.

Marks for strap placement

Fold the end of each strap over by 1/2” and pin the folded edges of the straps 2” down from the top edge of the hem and 2.25” from the centers of the main panel. The inner edges of the straps should be 4.5” apart.

Position straps on bag

Sew the strap ends to your bag. Sew a rectangle 1/8” from the edges of the strap and 1/8” from the top of your bag. Next sew a line dividing the rectangle into two squares and sew an “x” through each square.

Sew straps onto bag

Your square bottomed shopping bag is now ready to use!

Here are some photos of my finished square bottomed shopping bag:

Bottom of finished bag
Front of completed bag


Square bottomed shopping bag for carrying square egg carton flat

The 30-pack of eggs that I buy in a square carton fits flat inside my square bottomed shopping bag. There is plenty of room inside the bag to hold light items on top of my eggs. This bag also makes it easier to stack some rectangular items next to each other. I look forward to getting my eggs home without them leaving their compartments in the egg carton. I hope this square bottomed shopping bag makes shopping easier for you too :).

Did you enjoy this square bottomed shopping bag tutorial? Subscribe so you don’t miss a post. Comment below and/or Pin Me for later.




Help support Sewn By Tanya

If you love what I do, have learned from reading my blog, and/or want to support my work financially, consider becoming a Sewn By Tanya patron. Your monthly donation of $1 or more will help Sewn By Tanya grow and expand. A minimum $6 per month gives you access to Sewn By Tanya Patreon only content. There’s so much I’d love to do and you can help make it happen.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.