.......only 15% smaller just like this petite one I made for her daughter!
I often make a bag bigger or smaller than the original. Above you can see several "Sherbet" bags from a pattern by Melly&Me. The original size bag is the smallest one at the top (completed size 19" including handles). My sister asked for a bigger one, so I made one 50% bigger (the one at the bottom). As I had bought the paper pattern, I took it to the library and they enlarged it on their big photocopier. Sadly sis said that one was too big, so I made another one just 25% bigger (the one in the middle).
This one is the The Josy Clutch from Ithinksew. The original pattern (top right picture) is for a bag 10 1/2" wide and 7 1/2" high. I made mine 25% bigger and then made another one for my sister using the rest of her black and white fabric!
1. The first step is to print the pattern pieces in the new size. To reduce it by 15% you need to print it off at 85% instead of 100%. To increase it by 25% you need to print it at 125%. My PDF print menu has a 'Custom Scale' box where I can punch in the size I need. If all else fails, you can use the copy function of your printer to reduce or enlarge the full-size pattern pieces. Mark all the pattern pieces clearly so not to mix them up with the full-size ones!
"Sherbet" by Melly&Me, available as pdf or paper pattern
2. I use the same seam allowance as for the original patterns.
3. When it comes to positioning (i.e. 2" from the top) I do a quick sum to adjust it. To be honest I usually switch to the metric measurements as they are easier to work out! I jot the alternative measurements in the margin of my instructions so they are there for next time.
Otherwise, it just requires a little thought. For instance on the smaller Stow-It-All bag, I left the front pocket undivided, as three sections would be tiny, and two wouldn't work with the twist lock in the middle. On the back of the bag, I split the pocket into two.
Inside I used the full-sized zipped pocket pattern piece as the smaller one would only take a 6" zipper and that's too small for me. I checked it would fit first! I used the smaller slip pockets, and divided them with a 1" pen slot. See how well my stripes matched!