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Bento bag with my stash

Bento bags are a great way to carry small goods. Individual produce bags for your fruit and veg, wrap a present in or my favourite a project bag.

I found these little treasures are a gem to pop in my bag. They're a pint sized replacement to my other project bags. Small projects pop straight in and protected from the unspeakable rubbish that lurks in my handbag.

There are numerous blogs and instructional videos into how to create them. There are two main methods, one starting with a square piece of fabric and the other a rectangular piece.

These bags don't require a pattern and both will give you the same result.

In this version I want to walk you through not just the 'how to' but also how to problem solve the measurements to fit any size fabric piece.

My main aim was to adapt whatever fabric remnants or old clothing I had stashed. Particularly while I’m practising I don’t want to invest in new fabric. Or if this is a plastic bag replacement in your produce shop, used fabric is perfect!

To know which method you’d like, to start with you'll either need a square or rectangular piece of fabric.

Lessons learnt:

I confess I'm a lazy sewer, I don't always press my seems and if something doesn't fit I'll try and fudge it. Apologies to those skilled sewers reading this, I'm sure you've cringed.

But being precise is key here! Particularly for the rectangle technique, it really matters, odd lengths will leave you with a warped bag when compiled. I'll show you later what that looks like.

  • Be precise

  • Press seams

  • Light to medium weight fabric works best

  • Keep to the grain line, could be tricky keeping sides aligned if working on the bias

  • Don't go too large with bag, it'll loose its shape


The first and in my mind the simplest is the square. This method was perfect for the back of my hubbies old work shirt. I'm going to work in centimeters, these are sizes I've fiddled with and found worked.

Small: 30cm x 30cm

Medium: 50cm x 50cm

Large: 70cm x 70cm


I've used an overlocker on these seams. Either leaving them exposed or turned once to hide the seem. If you don't have an overlocker, I would do a zigzag stitch over the edge. It's your choice what seams you'd like to use.

Working from scraps:

Figure out what size square you can get out of your remnant or fabric piece you've chosen.

Before you commit you can work out the size bag. To do this you'll need to figure out the diagonal length (hypotenuse) of the triangle.

If you have a 50cm x 50cm square you'll have a diagonal of 70.7cm. Half the diagonal is 35.4cm which will be the height of the bag and also the width of the base.

To find out the hypotenuse of your triangle, you can either use your high school math skills or this easy link to a hypotenuse calculator. There are others out there, I just found this user friendly.

Lets start:

  1. Cut a square

  2. Cut a diagonal across your square. You'll have two equal right angled triangles.

3. Overlock the shortest lengths, turns and press onto the wrong side of the fabric. You can leave the diagonal for now, it will be sewn together later.

4. When pressing the seams, I also folded the triangle in half and pressed the half waypoint of the diagonal as a marker.

5. Lay the two triangles on top of each other, both face up. Align the triangle tips to the halfway point on other triangle side. Leave a space for the seam allowance. I left 1cm space to overlock it.

6. Pin in place.

7. Refer to the image below, starting with the blue line. Sew from one corner to the tip, then back to the other corner. Do the same for the orange line. from the right side or the wrong side I don't think it matters.

8. Fold in half with right sides together. This image was taken before step 7. You can double check that it aligns before sewing.

9. Pin sides of the bag in place.

10. Overlock seams

Your bag can be used at this point. What I would recommend is sewing down the corners of the base. This will enable it to sit flat on the table.

11. While the bag is inside out. keep the base flat on the table.

12. Again another triangle. If you'd like a 10cm deep base, measure 7cm up both sides of the corner of the bag. With a ruler mark a line across, pin in place and sew.

You can vary the depth of the base but be mindful the height varies with the depth.

13. With an over locker or sew straight across the corner. The overlocker will cut off the excess triangle. leaving it there is also fine, I did this in the rectangle section.

12. full bag in the right way. You can see clearly on the images below, the base sits flat.

Nice work, you're done!

Here's two other options with repurposed and remanent fabrics. Both with a raw overlocked edge. I love them.


Start with a rectangular piece of fabric. The length will be 3 times the width. Or the width 1/3 of the length. Brief reminder, being precise matters in this version. Odd ratios of length to width will produce a warped bag.

These are good sizes to work with. I would keep to these if you're keeping a raw (overlocked) edge.

Small: 45cm/ 15cm

Medium: 75cm/ 25cm

Large: 105cm/ 35cm

Before the bag is sewn together, all sides of the fabric are hemmed or overlocked.

So know what seam allowance you're going to use before you get cracking on this one.

If you start with the sizes I listed and then choose a rolled hem, lets say 1.5cm seam allowance, the sides of the bag won't reduce at the same percentage.

See how the sizes change.

Small: 45cm/ 17cm

Medium: 75cm/ 27cm

Large: 105cm/ 37cm

Lets start:

In this project I've used left overs from a top I made. I bought a little more than I needed. I wanted to use as much as I could with no waste. I measured out the width of the fabric (its folded in half here), I have a length of 105cm.

If I chose a raw overlocked edge my width would be 105/3= 35cm

I've chosen a 1.5cm rolled hem. I choose this because it's a nice clean finish and not a too fiddly to do. If you find this bulky, choose a 1cm rolled hem.

Starting with the length, there will be 1.5cm seam allowance on either side, thats 3cm in total off the 105cm length = 102cm when finished.

We need to work out the finished width without seam allowance. 102cm / 3 = 34cm

Now add in the 3cm seams allowance. 34cm + 3cm = 37cm

1. You'll need to cut a 105cm x 37cm piece of fabric.

2. Press, pin and sew around the whole rectangle.

3. Lay right side up.

4. With right sides together, fold 1/3 of the fabric over. Check that the folded section is the same measurement as the width.

5. Pin one side in place

6. Fold the other 1/3 over, check measurements and pin in place on the other side.

You will need to fold the previous un pinned 1/3 out of the way to pin the second piece in place.

7. Sew both sides in place. Both sides should be able to open like this.

Your bag can be used at this point. If it doesn't lay flat like the below left image, skip to the trouble shoot section at the end. What I would recommend two more things, sew down centre fabric fold at the front and the corners of the base.

See the images below. The seam allowance sticks out a little, by sewing the inside seam flat to the front gives it a tidier finish.

8. From the right side of the bag, pin with the seam allowance pointing up and sew.

Sewing the base is

9. With the bag is inside out. Keep the base flat on the table.

10. Again another triangle. Larger bag so I went with a larger base of 12.5cm.

Measured 9cm up both sides of the corner of the bag. With a ruler mark a line across, pin in place and sew.

You can vary the depth of the base but be mindful the height varies with the depth.

11. I kept the corners in place and sewed a straight stitch across.

Nice work you're done!

Finished measurements:

The finished width is what you need. Use the hypotenuse calculator. In this project the square was 34cm which is 48cm along the diagonal. The height and width of your bento bag is 48cm.


Picture says a 100 words, my first trial didn't go as planned. If your bag looks like this, swear at it or walk away but don't stress it can be fixed! You haven't wasted your fabric.

  1. Lay it back out flat as a rectangle

  2. Fold in the first 1/3, checking your measurements (steps 4 - 6) make sure its a square.

  3. Fold the other 1/3 over the top and measure what excess is there.

  4. If you have 10cm excess and you used a 1.5cm seam allowance, cut off 8.5cm.

  5. Press the seam as before and sew in place.

  6. Continue with the above steps to complete the bag.

I hope this helps your trouble shoot making a practical, versatile bag that can maximise the fabric you have. Don't throw out, use that old dress, shirt or even a tea towel and share your creations! #thislushcorner

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