Thanks to technology, enlarging & reducing patterns from a digital .pdf document is pretty simple. But if you’re worried about getting the details just right the first time, here are some tips for how to handle it so you can jump right in!

What’s your percentage?
Determine what percentage you want to increase or decrease the project by looking at the finished size. This should be listed on your pattern. Focus on one measurement (such as length or height) and decide how much bigger or smaller your want that measurement to be. Divide the desired size by the original size.
Dolphin: 5” long vs. dolphin: 8” long = 160% increase


Next up is to dial in that new percentage you calculated:
Open up the print dialog box.


Type in the pattern pages you want printed.


For decreasing: set “Custom scale” to your percentage (should be less than 100%). The page will print a smaller image on the same sheet.


For increasing: click on the “Poster” button.


Set the “Tile scale” to your percentage. This will split one page up into 2 or more pages each.


The “Overlap” setting is how much the split pages will print the page adjacent to it. The finished pages will overlap once assembled. I think this makes assembly easier, and I go with .5”.


Hit “Print” and print out all the pages for your newly enlarged or reduced pattern.


If you have an enlarged pattern, your pattern pieces will need to be taped back together. Assemble the pattern pages by lining up the matching edges. Use the original document as a guide.


If your pattern included seam allowances, they’ll be inaccurate now because of all the scaling. Here’s how to add them back in:
You can use the pencil method: This is done by rubber banding a pencil with another pointy object (such as another pencil, a chopstick, or a pencil with a spacer). The goal is to have the points spaced out enough to equal your seam allowance. Measure the distance, then adjust the pencil as necessary to make it work.


Once you’re ready, run one side of your new seam allowance pencil along the seam line of your pattern. The other end will then draw parallel to it. Drawing two lines at once automatically gets you a new seam allowance! If you do this with a reduced pattern, you might want to trace it onto a new sheet of paper to avoid overlapping the other pattern pieces.
You can also try the ruler method: Find an accurate ruler (preferably a small one), such as a seam gauge, quilting ruler, or even a scrap of cardboard with your seam allowance marked on it. Align the mark equal to your seam allowance on the seam line, and make a dot with a pencil. Move the guide along and draw marks around your pattern piece, then connect the dots to complete your new cutting line.

Now you have your new pattern pieces, and you can cut and sew them up as usual!