Enlarging, reducing and modifying PDF patterns is a good skill to have. You should be able to adapt a pattern to work for you! I am always adding a pocket or changing the strap length, and I don’t think anyone should be afraid to modify a pattern! If you are unsure about it, try making the pattern once at 100%, and then once you are comfortable assembling it according to the instructions, go ahead and make some changes!
For example, here are two wallets I made with a Keyka Lou Pattern, which is a medium sized wallet. For the Apple Dot wallet, I added 1/2″ to the middle so it would fit my iPhone. I reduced the size of the blue wallet (to about 80%) to fit credit cards, and I eliminated one of the pockets.
When reducing or enlarging, I recommend staying within the 80%-120% range. Any more or less than that you might have to make additional changes. If you have a tote bag that is 8″ wide by 10″ high by 4″ deep, and you enlarge it 120%, it will be roughly 9.6″x12″x4.8″. I just multiplied each number by 1.2. Seam allowances already included in a pattern piece change this a tiny bit, but if your SA is 3/8, enlarging the pattern by 120% doesn’t even bring your SA up to 1/2, so just keep the 3/8 and you will be fine! This is often helpful if you have something you would like to fit into your bag, like a laptop, and you aren’t sure how much to enlarge the bag.
Depending on how close to the margin the pattern piece is, you can probably enlarge it a little bit on your printer at home. (Reducing is the same process, but you should always be able to reduce the size!) Here is how I do it on the Mac. Windows is similar.
I opened the PDF in Preview and went into the print menu. Normally you want to make sure the scale is set to 100%. To change it just click in the box and type what you want (Here I chose 115%) and then hit “tab” key to see how it will look in the preview window:
You can usually squeeze a little bit out, but at some point it will be outside your print margins as seen here:
If you can’t make it large enough with your printer, you still have some options. You can take the printed pattern pieces to a large-format copy machine. (Most large copy machines will do large format 11″x17″ paper, just not the home all-in-ones.) My library has one that is 10 cents a page, but I have to ask the front desk for the large paper or bring it myself if they run out. So take it to the copier and pay close attention to the arrows so you know where to line it up and pay attention to which drawer and paper size it is using. Prepare to mess up a few :) Don’t worry, copy machines are not scary, but please – as someone who had to unjam them ALL THE TIME at my last job, ask for help! The person in charge would rather help you than fix a paper jam later. I promise!
Now, if you just want to make something taller or wider, especially a pattern with straight pieces, all you need to do is slice the pattern down the middle and add some inches!
Here I will show you a pattern piece from my Quick Zip Lunch Bag, a small lunch bag that can easily be enlarged even without a copy machine.
So, this will make the 2″ bag wider, without changing anything except the required zipper length.
Next, say you want to make the bag taller.
I rolled out a piece of art paper a (The art paper is from Hobby Lobby, it was like $3 with a 40% off coupon. I tape it to my mat with painter’s tape. You could also use freezer paper or tape several pieces of paper together!) I lined up my ruler with the 1″ line on the bottom of the pattern and drew a line. I arbitrarily chose to make it 1″ taller.
Then you have a couple options. You can simply extend the line for the side of the bag, and use the same instructions in the pattern to box the corners and it will be relatively the same depth. If you want to make the bag DEEPER, you will need to extend the sides OUT a little bit, and then when you come to the boxed corner portion of the pattern you will need to measure in a little bit more and sew a larger triangle. If you want to go a lot deeper, you should make the bag more than 1″ taller as well. If you go out 2″, maybe also increase the height 2″. This is not difficult but you do need to have a little more faith in yourself and be willing to take a small risk! You can pin it and turn it inside out to get a feel for it if you want, before you sew. You can also cut out a mock-up from paper and tape it together, just make sure you take seam allowances into account.
See all the options? Nice, huh? Now for a rectangular tote bag, it’s even easier. Just keep in mind that if you want the bag to be deeper, you will be cutting off more for the boxed corners so you need to make the bag both taller and wider, and then sew and cut off a larger triangle. I promise it’s easy to do!
Some things to keep in mind:
If you are using a specific size of hardware on the straps, you don’t want to change the width of the strap. On the other hand, you might want a wider strap even if you don’t change the size of the bag. Just make sure there is room on the sides to sew a wider strap. (For example, don’t put a 2″ strap on a messenger-style bag that is only 1″ deep.) And I almost always lengthen straps – this is completely personal preference.
Most pattern pieces should be increased proportionally, but in some cases you want to make sure the changes aren’t too drastic – for example with an inset zipper on the Quick Zip Lunch Bag, you don’t want the zipper to dip down too far. If you increase the bag more than 110%, you might want to keep the same height of the top lining band and add the height to the bottom lining piece instead.
It’s important to be consistent. If you want to change the shape of a piece, be creative and do it! Just make sure you change the lining and pockets too! You can still follow the basic construction directions. If you aren’t sure, baste it or pin it together and turn it right sides out to check the look!
Take into consideration something like a pocket sized to fit credit cards, or anything that needs to be a specific size.
Not everything successfully can be enlarged by a %. When I made the two sizes for the Notepads pattern, I had to base it off of the size of the pad of paper, and so the two sizes are not just a % difference. In some cases you’ll need to do some math!
FABRIC & SUPPLIES
To figure out how much fabric you will need for a larger size, cut out all of your pattern pieces and lay them out on your cutting mat or on another piece of fabric. (Cotton fabric is usually 20-22″ wide when folded in half.) Some projects will only need a little bit more fabric, but some use up every last inch of fabric listed in the requirements – pattern pieces that used to fit side by side might not any more – and you will need more so keep this in mind. You will also need more interfacing and longer zippers.
If you want to make something out of a favorite fabric but don’t have quite enough, consider reducing a pattern by 90% or 95%. It may be an insignificant difference to you, especially if you get to use your favorite fabric!
OK, did I cover everything or did I just make it more confusing? Any questions?