How to Adjust the Size of a Boxed Zipper Pouch / Super Easy Formula
Zipper pouches are one of those projects you can never have too many of—practical, cute, and surprisingly simple to sew.
But what if the pattern you’re using isn’t the size you want? Do you cross your fingers and hope for the best?
Nope—there’s an easy formula you can use to make your pouch exactly the size you need.
In this post, I’ll walk you through the simple math behind resizing a boxed zipper pouch.
Once you understand this, you can create pouches in any dimension—perfect for makeup bags, snack bags, or even overnight totes.
Why Adjust the Size of a Zipper Pouch?
- Maybe you saw a pouch at the store and wished it were just a bit taller.
- Or perhaps you need something smaller to fit earbuds, lip balm, or a little collection of sewing notions.
Instead of hunting down the “perfect” pattern, you can adjust what you already have.
By using this formula, you’ll be able to:
- Scale a zipper pouch up or down.
- Customize the depth and width for your needs.
- Always know how big to cut your panels and the dimensions of your box corners.
Step 1: Decide on Your Finished Size
The first step is determining how large you want your bag to be.
Tip: Use an existing pouch or gather the items you plan to store in the bag.
Set them side by side to get a sense of the dimensions you’ll need.
For example, I wanted a little overnight pouch to hold facial products. After measuring, I decided:
Length:: 5 ½ inches
Height: 5 inches
Width: 2 inches
CLICK ON THE LINK BELOW TO GET THE FREE PDF.
Step 2: Use the Formula
I recommend downloading and printing this form so you can have it in front of you for visual reference.
Otherwise, I find it’s too easy to forget or get the measurements all mixed up, which can result in the wrong size panel being cut out. (Believe me, I have done it more than once!)
Every pouch starts as a flat rectangle of fabric.
To figure out the size of that rectangle (the panel), use this formula:
Horizontal Cut = Desired Length + Desired HEIGHT+ Seam Allowances x 2 (X 4 IF USING FRENCH SEAMS)
Vertical Cut = Desired WIDTH + Desired HEIGHT+ Seam Allowance x 2
For my example:
HORIZONTAL CUT = DESIRED LENGTH 8″ + DESIRED HEIGHT 8″ + 1 1/4″ (for French seam allowance) = 9 1/4 inches
VERTICAL CUT = DESIRED WIDTH 4″ + DESIRED HEIGHT 8″ = 12″ + (seam allowance) 3/4 inces = 12 3/4″
So, each panel would be 12 3/4 9 1/4 X 13.
You’ll cut:
2 panels of outer fabric
2 panels of lining
Stabilizer (optional, same size as panels)
Step 3: Figure Out the Zipper Length
Your zipper length = DESIRED WIDTH plus 1. I like to cut it at least 1/2 inch longer, just to be safe.
If you’re using zipper by the yard (which I love). Cut it to the desired length.
If you’re using a store-bought zipper, choose the closest size and trim if needed.
Step 4: The Secret to Box Corners
Box Cut = 1/2 of the desired finished height minus 3/4 inch seam allowance.
Tip: Always account for the seam allowance when marking your box corners!
Measure from the seam and the fold, NOT THE FABRIC EDGE.
Step 5: Mark and Cut Correctly
There are two primary methods for marking box corners:
- Before sewing the side seams, lay your panel flat and cut the square directly from the corners, ensuring you add the seam allowance.
- After sewing the side seams, mark the box cut and then cut. (Measure from the seam).
Either way works—it just depends on your pattern and personal preference.
This is an excellent tip: when you’re making that box corner, this little square ruler comes in real handy.
You can use a regular ruler, your own, or another type of template that you prefer.
By placing a piece of painter’s tape on the measurement of the cut, it will make it much easier on the eyes, and it will save you time from fidgeting around to find the lines again.
Step 6: Keep Notes
I highly recommend jotting down your measurements on a printable chart (I created one for you—download it free below!).
This way, you won’t forget your panel and zipper dimensions the next time you want to make the same size pouch.
Write down:
- Finished bag size
- Panel dimensions
- Number of pieces to cut (outer, lining, stabilizer)
- Zipper length
Final Thoughts
That’s it! With just a little math, you can make zipper pouches in any size you want.
Whether you prefer a tiny pouch for earbuds or a roomy overnight bag, this formula will take the guesswork out of resizing.
✨ Try making a few different sizes—you’ll be surprised how versatile these pouches can be.
My snack bags, for example, use a larger box corner so they stand upright, while some of my cosmetic bags use a much smaller corner for a sleeker look.
Happy sewing—and have fun making your perfect pouch!
Jan Howell
Share:
Connect:
Step 3: Figure Out the Zipper Length
Your zipper length = DESIRED WIDTH 5 1/2 + DESIRED HEIGHT 5 + 2 INCHES. I like to cut it at least 1/2 inch longer, just to be safe.
For this example:
5 ½” (width) + 5″ (height) + 2″ = 12 ½ to 13 inches.
If you’re using zipper by the yard (which I love). Cut it to the desired length.
If you’re using a store-bought zipper, choose the closest size and trim if needed.
95 Comments
I can’t seem to get the info sheet on sizing the pouches. I walked through the “robot” issue 2x and used a different email to see if that would work. I’d love to have it.
I just sent you an email with the PDF. Let me know if you don’t get it.
-Jan
I also could not find the pdf on smaller makeup bag sizes
Thank you!
Here are the links to a few of my bags. The size measurements are in the descriptions.
https://www.etsy.com/listing/478238616/essential-oil-cosmetic-clutch-pdf-sewing
https://www.etsy.com/listing/1608850728/scrappy-quilted-zipper-pouch-pdf-sewing?ref=shop_home_active_6&crt=1&sts=1&dd=1&logging_key=975bd789f62b57fa5dc105f98a6cede4ce41aad3%3A1608850728
Hello, so excited about these, but I can’t find the link as per above. Can you please let me know what the steps are? Many thanks
Hi Heidi,
Thanks for reaching out. I will manually email the PDF file to your email address: heidi@Rubyblue.net.au
Let me know if you don’t get it. fibersandtwigs@gmail.com
Could I get the pdf?
I just emailed you a copy. Enjoy.
Hi this sounds like such a wonderful way of getting your own sizes makes things a lot easier than searching for the correct pattern. I can’t seem to get this file I’ve downloaded the link and it’s just showing me 4 pictures on the file nothing else is there anywhere else I can try save this from? Thankyou
I will email you a copy right now.
I also went through the steps to get the PDF sizing worksheet, but could not get the file.
Hello, I will send the PDF to your email. Send me an email jannihowell@youmaketisimple.com if you don’t get it.
I can’t seem to get the file from the link.
I will email it to you.
Here is the link
https://drive.google.com/file/d/101iJaOrJVqYJPVXQaEt3uiQ17bwfmiMQ/view?usp=sharing if you want to download from here.
I can’t find a link to the info sheet on sizing the pouches.
Hi Jennifer,
I will email you the link now.
I love this post, but I don’t seem to be able to find the link to the printable chart.
Thank you.
Hi Tina, the link is in the post. Click on the ornage box. Here is the link.https://youmakeitsimple.com/wp-content/uploads/2025/10/BOXY-POUCH-DIMENSION-FORMULA-6.pdf
If you can’t donwload it from here let me know, and I can manually email it to you.
Oh thank you so so much for this information. I just started making zipper pouches and have spent countless hours trying to find the right patterns. So many tutorials are not clear or there are so many extra steps.
I have been adding a ruffle next to the zipper and I am just obsessed with how adorable they are.
Thanks again!!!
Amanda in Alaska
Hi Amanda,
You are so welcome. I’m glad to hear you enjoy making zipper pouches. I love the idea of adding a ruffle. It would be fun to see them. If you’re on Instagram, you can tag a photo of your pouches @youmakeitsimple. I think everyone would love to see them.
Thank you for sharing the formula. But could it be a mistake that the box should be 1/2 the depth? I would say 1/2 the hight, as the seem from the folded box creates the hight of the pouch, and the remaining fabric, when the boxes are cut, will create the depth. The smaller the box, the more flat the pouch. With kind regards, Mette (Denmark)
Hello Mette,
I just emailed you the updated version of the PDF. You are correct. The formula and PDF have been revised as well as the blog post.
This is really useful, thank you. could you send me the updated PDF please? It’s not letting me download.
I just emailed you the updated copy. Let me know if you don’t get it.
Email me at fibersandtwigs@gmail.com
This is so great. Can you email me the pdf please? Thanks for this info!!
I just emailed you a copy. I hope you find it helpful.
Hello. Would you please e-mail the pdf for the measurements. Thanks so much!
No problem. It’s on it’s way.
Would love the PDF for this project. You make it so easy to create these bags. Thank you
It’s on it’s way.
Dear Jan,
I would like to make a boxy bag that is deeper at the bottom than at the top.
2 1/2” at the top and 3 1/2-4” at the bottom. Do I just make my box cuts different size? Would I have to change any other dimensions,(such as the zipper length or the shape of the flat rectangle pieces)?
Hi Mary,
Thanks for reaching out.
Oh tha’ts a good question.
I have never thought of doing that or seen anyone make it up.
Honestly, I don’t have a for-sure formula for you.
You would not need to adjust the zipper size. Still figure that measurement as before.
It’s that boxed corner measurement that would change.
As you said, I would make the top box cut 1 1/4 “- seam allowance, and the bottom 2” minus seam allowance.. (for a 4-inch bottom)
It will affect the panel size. To get the panel height, add the desired depth (which is the total of the top and bottom divided by 2, plus the seam allowance). I hope that makes sense.
Put that into the formula to decide your panel size.
I would probably do a test bag using scrap fabric before I tried it on your final product.
Let me know what you think and get back to me if you have any questions.
-Jan
Hi Jan,
Did you include the printable chart link that you talked about when you were saying to write down the measurements so you can recreate the same size later? I couldn’t find the link. I would love to have it. Thank you so much
I just sent an email reply with the link. But if you didn’t get it, here is the link. https://drive.google.com/file/d/194O0rvkKwI8V-FudTLzi7b_vmyzoniKy/view?usp=sharing
Hi. Thanks for the updated formula. I still have a problem.
In calculating the Width of fabric panel to be cut out I do not understand why one would add the width of the bag to the height of the bag. I calculate using the reguired width plus the required side depth plus 2 x seam allowance. Same for french seams.
W = WIDTH + DEPTH SIDE + SEAM ALLOWANCE (X2)
W = 5 1/2″ + 2″ + 1″ (2 x 1/2″) = 8 1/2″ your bag would be
W = 5 1/2″ + 5″ + 1″ (2 x 1/2″) = 11 1/2″ Your example
H = HEIGHT + DEPTH BOTTOM + SEAM ALLOWANCE (2) okay.
Can you let me know if I have misunderstood something.
Thanks Marie
Do you have the latest PDF download.
It states Pandel width = desired width + desired height + seam allownane x 2 (French seams – x 4)
I know it may be hard to wrap your head around, believe me, I know. But I can assure you this is correct.
I will email you the latest copy, just to make sure you have the edited version.
Let me know if you have any questions.
Maria –
In Jan’s formula, Width is the “depth” of the bag.
Because it is a BOX, the “Length” of the bag is the Desired finished length PLUS 1/2 the Width (Depth) on each side (that part that “wraps” around the corner on the left and the right), or 1 x the Width, plus 2 x the Seam Allowance.
Hope that makes sense.
Kim
Thank you for this! I made a rectangular bag for my curling iron. My 4 corner boxes were cut the same size but one side of my bag is a bit narrower at the top. I’m wondering if this is due to the thickness of the handle I sewed into one end (the now wider end). I did French seams. Any thoughts?
Hi Starla,
Yes, most likely the end where you added the handle, the seam was bulky and after sewing it doesn’t open up as much as the other side. You want to make sure you trim down those seams, especially the bulk from the handle. Depending on where you are with your project you could instead of unpicking, make the other side seam a little bigger to accomodate for this. Otherwise, chalk it up as a learning experience for your next bag. Let me know if you have any further questions.
I am very new to sewing so my question may be a silly one, please forgive me. If the finished bag is 5 1/2″ wide, why is the zipper 12 1/2″ long? Wouldn’t it be 7 1/2″ (width + 2″)? Why do you add the height into the equation (w + h + 2″)?
I know it is hard to wrap your head around.
It’s width + height + seam allowance x 2. Not 2 inches.
What is the desired height of you bag?
If you follow the equation, it will come out correctly.
You have to account for the height because the width of the panel wraps around the side of the bag.
Oh, I see! Thank you
You’re welcome.
Could I have the PDF, please?
I just sent the PDF to you. Let me know if you don’t get it.
Thanks for this amazing tutorial! I am new to sewing pouches and now understand this concept. I would be grateful if you would send me the pdf worksheet for this🙏🏻. Thanks
No problem. I just emailed you a copy.
Could you tell me how Tim get the pdf worksheet, please.
I will email a copy to you right now.
I can’t find the link to the pdf
I will email the PDF file to you now.
Hello! You speak of a newer boxy pouch PDF file if using French Seams in your very recent posts. Thot I saw a copy where there was a measurement (for something!) of 1 & 1/4″ if using French Seams, however, I can’t find it again 🙁
I did notice the x4 on the seam allowance on an apparently updated copy maybe marked Form #10? Nothing happens when I Click on the Free PDF Download button, how may I get the latest PDF form? Btw, your tip on how to avoid having to sew a seam on the inside fabric @ the bottom of the boxy bag = fantastic! Thanks!
I will email the updated PDF now for you.
Hi, Jan. Sorry to be a pain. In the example for determining panel width, it says 8” width + 8” depth + 1” for seam allowances (8+8+1) = 16. I’m thinking 17”. Ditto on the tip regarding the inside fabric at the bottom of the bag.
What is the disired height, width and height of your finished bag?
I am going to send you the latest file to make sure you have the updated and correct version.
Let me know if you still have questions.
Hello! Many thanks for the updated boxy bag formula! 😊 I’m a bit confused on the formula for the panel heighth, tho.
Page 2 says “add your desired finished HEIGHT to your desired DEPTH (+ 2 times the seam allowance you’re using.), but the written “math” equation right below says to “add your desired WIDTH (not heighth) to your desired DEPTH (+ seam allowance, etc) to equal the panel heighth. Where am I going wrong?
Many Thanks!
It looks like I sent the wrong file. I will send the updated file right now. Let me knowif you still have concerns.
This is a wonderful tutorial and formula! Would it be possible to get the PDF? I am having trouble getting to it from here. My daughter asked me to help her make a boxy bag.
Thanks,
Victoria
I will email it to you now.
Hello! I see in your reply that you were sending the updated file.
Unfortunately, it did not come thru. When able, can you please
resend it. Thanks much, Kerry
Is this the email eliza140@aol.com
You may need to check your spam folder.
I will resend it.
Hi Jan! Yes, that is the correct email & your resend DID come thru yesterday (nothing was in spam folder)…thank you so very much! Can’t wait to use it! Instead of boxing the corners, I’m going to try measuring in from the tip of each corner, then angle-sew across the corners thus making triangles, then cut off the excess leaving 1/8-1/4″ edge, then sew the last french seams to make the boxed corners. Unsure of the outcome as flying by seat of pants on that…yikes! Many thanks again for your tutorials!
You are so welcome. Let me know how it goes.
Thank you so much! This will come in handy!
Glad it was helpful.
Hi there! I love your content. I would like a copy of your sizer pdf if possible as I cannot seem to find the link.
Keep crafting!!
Thanks Tracy for your kind words. I will email you a copy of that PDF.
Let me know if you have any questions.
Thank you for a good explanation of dimensions for a blocked corner.
You are so welcome.
Hi Jan! I love your method for these boxy pouches with the French seams and I’ve bought the Etsy pattern. I made one pouch that came out several inches too small across the long side and realized that there must be a newer version of the formula pdf. Would you please send it to me at churt301@gmail.com? Thanks so much.
I just emailed you the updated PDF.
Thank you so much for this tutorial and PDF. I’m trying to make a custom boxy bag that will fit a specific box that measures 3.5”W x 17.5”H x 2”D. Tall and narrow.
From my measurements, the panel width would be 22”. I can’t wrap my head around that when I need the finished width to be 3.5”. I got a measurement of 20.5” for panel height. That measurement seems correct.
I also need guidance on the zipper length. I only need the zipper to go down the sides maybe 1-2 inches. So seemingly only about 10 inches would be needed. Any advice for making this sized bag?
Hi
Thanks for reaching out.
If you want your pouch to be 3.5 wide, 17.5 high, and 2 deep
Your panel width would be 12.5
panel height would be 20.25
Zipper length would be 13.5
For this type of pouch and this pattern design, the zipper will go halfway down the sides of the bag.
You can’t just have it go down a few inches.
The zipper length would be 13.5 inches.
Do you have the PDF? I’ve included the updated one just in case you have the old one.
Let me know if you have any questions.
Enjoy the weekend,
Jan
Why want it open the pdf?
I will email you a copy. Let me know if you don’t get it.
This is helpful especially since I need to see it to understand. Can you send me the PDF formula sheet. It will be most useful! I love to make these box bags as gifts. Thank you.
No problem. I will email that to you right now.
Hi Jan!
I’m a new sewer and I used your tutorial to make a box bag. I love the method without the awkward liner seam, and the French seams were way easier than I anticipated. BUT I used your formula to determine the width an my box ended up much narrower and with greater height. In fact the height was 2x the box cut out. I think maybe I was looking at an old version of your pdf. Could you send me the updated version? Thanks so much.
Yes, it sounds like you have the old version. I will email the new one to you now. I’m so sorry about the confusion.
Hi Jan, This is such a wonderful idea. I tried to find the updated PDF that you are using in the video and I was unable to find it. Is it available?
Here is the link
https://drive.google.com/file/d/1Y6lhmQhF5UMYBR4q2rfeEdHowHpo0iAg/view?usp=sharing
Hey – just FYI – this link you sent here as a reply comment works fine but the one in the blog post links to a .ppp file that can’t be opened, not a pdf file. Just wanted to let you know. I love all of your videos! So easy to follow and I’ve made several things by watching and following your tutorials!
Hello Jean-Marie,
Thanks so much for bringing this to my attention. I have fixed that. I appreciate you reaching out!
Have a wonderful day my friend.
Could I get the updated pdf please thank you
No problem. I will email it to you right now.
Your tutorials are great and I really appreciate the pattern for the boxy bag. However, I and trying to make a very large version to store some camping equipment in. My finished dimensions need to be 33” wide, 25” tall, 6” deep. Using your formula I came out with a Panel Width 59”, Panel Height 32” ( using 1/2” seam), Zipper 60”. What I’m really confused about is the BOXED CUT. The directions I have say 1/2 desired finished depth, minus seam allowance so my box would be 21/2”. I still have to sew the box shut losing another 1/2”. In my mind my finished depth would no be 1” short, only 5 total inches. Please help me understand how these measurements would get me to a 6” depth. Seems to me I would be adding, not subtracting the seam allowance???
Thanks for your help with this. I can’t dare cut the very large bag until I am sure. Bev
Hi Beverly, my first question for you is: are you planning on sewing French seams and a 1/2 inch seam allowance? If so, your panel would measure 60 inches wide x 32 inches high. Aipper length 61.
The box cut would be 2 1/2 inches.
As far as the boxed corner measurement goes: when you are at the step where you mark the box cut, you start the measuring from the SEAM ALLOWNCE AND THE BOTTOM FOLD OF THE BAG, not from cut edge to cut edge. That accomadates for the seam allowance x 2, because there are 2 seams. I hope that makes sense. https://youtu.be/E5dQ5sFrt-I?si=sp6u2FqlTCXKPVdT&t=548
This clip will help you understand.
If after watching this, you still have questions, let me know.
Hello! I love this tutorial! However, I’m unable to get the pdf to download. Is there another way I can get it? Thanks!
I will email you a copy right now.
Great tutorial. I, also, am unable to download the PDF file.. I can’t wait to make a bag wither size I want
I will email you a copoy right now. Let me know if you don’t get it.
I woukd love to have a copy of the pdf for the measurement changing guide. I can’t seem to find it. Pls help.
Here is the link.
https://drive.google.com/file/d/1uYxf780H09Lcjx8xvmUHoEQCFmSA85iN/view
Jan you are the best! I bought your zipper boxed pouch pattern and I was thinking how I could formulate the formula to make different sizes. You beat me to it. Your pattern will get in use especially Christmas time. Thank you so much.
Hi Ako,
Glad to hear this will be helpful for you. Have fun making zipper pouches.