I was asked how to grade up a size in bra patterns. I’ve done this with a few patterns now, so I’ll share with you what I do.

First off, I simply pulled out the nearest pattern I had. It’s the Pin-Up Girls Classic, but any multi-sized pattern will work. I also gather any other supplies I’m going to need: a pencil, an eraser, paper, a seam gauge.

I put my pattern piece under whatever paper I’m using to make my new pattern piece – I use medical exam paper. I love it. It’s a little firmer than tissue paper, and I can see through it easily.

This pattern piece is the lower cup. I get out my seam gauge and measure the distance between the two sizes shown right here. For interest sake, I won’t be changing the gauge while I take photos – just to show you how the distances change throughout the pattern.

For this part of the pattern, you can see it’s 1/8″. As I move up towards the apex of the lower cup, I watch to see where that distance between the two sizes changes.

You can see here the distance has increased from the 1/8″. It’s not quite 1/4″ yet, but a little more than it was. As I go around measuring, I make little dots that I’m going to join together to form my new graded-up pattern. I keep checking (every two or three dots) to see if the distance is getting bigger or smaller. If I think it’s changed, I re-measure and if needed, re-set my gauge to make my dots at this part of the pattern.

In this photo, you can see a big change in the difference here at the underarm. Again, just to illustrate that point, I didn’t change my gauge in the photos. Obviously, to make the pattern fit properly, I’d change the gauge here and draw my dots accordingly.

Here at the bottom of the cup, it does get narrower, but I’ll show that in the next photo. What I want to make mention of here, is see all these little B markings? Take note of the distance between these too, and mark your new pattern piece. You’ll want to do the same at the apex mark and any other markings the designer has put on the pattern – they’re all there to help you and you’ll want them on your pattern piece.

In this last photo, you can see there is hardly any distance at all between the pattern sizes – maybe 1 mm. The gauge doesn’t actually go that small, so for that part I eyeball it. All the way along the bottom of the cup, the distance between the sizes got smaller and smaller. Just keep measuring and marking accurately.

The next thing I did was to actually go around and draw dots all around the cup using the measurements I’d talked about above. Those dots would not show up for a photo though, so here are a few of them joined together. You can join these dots freehand or have fun with your sewing tools and pull out your curved ruler. I like things to be nice and neat, so usually use my ruler to get the same shape as the original pattern piece.

I have only needed to grade up one size, and then only in the cup. So, for me, I’ve done this for the upper cup, lower cup and power bar. Then I use the custom cradle and bridge I’d made and insert the cups from different patterns into those.

You might need to grade up for each pattern piece. If you’re thinking of grading up, you may need to think about your cradle and bridge too. Just take your time, and measure the distances between every size on every part! Any multi-sized pattern will show you the difference between two sizes.

If you need to grade up more than one size, I’ve read in a couple of places, it’s best to simply buy a new pattern. I think that would mainly be for accuracy reasons.

Happy creating!