That’s a lot of math. As I prepare for the next steps in Caroline’s wardrobe, I had to work out the new measurements for the patterns. She is slightly larger than the actual patterns. 18.18% larger, in fact.

I had to ask my teenager for help. It’s been a long long time since I could easily work out the changes. If you are up scaling a pattern piece, here is a relatively easy method courtesy of high school algebra.

Find the measurement of one straight area of the pattern – I used any straight edge I could find.

Convert this measurement to decimal if you use fractions (US people, everyone else in the world uses metric, sigh). Multiply that new number by the percentage increase. Now add that number to your original measurement.

For instance, if your measurement is 2 5/8, this converts to 2.625.

2.625 x .1818 = .4772

2.625 + .4772 = 3.1022

Round that new number – 3.1

You can convert back to fractions if needed OR do what I did and eyeball those small numbers. .1 of an inch is a around an 1/8 plus a smidge.

A time saving tip is to add a 1 to your multiplication to save the addition step – 2.625 x 1.1818 = 3.1022

Once I completed all the math, I used my Pixelmator Pro to enlarge the pattern pieces, then printed them, traced onto tissue, and made all notes. I’ve also made a paper towel mock up of the bodice because the instructions just didn’t make sense at first. They include no illustrations of the sewing method, so gotta make sure I go slow and understand each step.

Hope this math workshop helps you in some way. Happy sewing!