How to draw an easy seam allowance around your bra pattern

The seam allowance around bra sewing patterns is much more narrow than the seam allowance for clothes. Do you wonder why?

Well, the outlines of bra patterns are mostly round, very round. Specially the cup parts and cut-out in the band are almost circle shaped. This will happen when you add a seam allowance :
The cup : at the rounding that fits under the breast (where the underwires would be) the outline will get wider and longer in length.
The band : at the round cut-out (where the cup has to be sewn in) the outline will get narrower and less in length.

This can cause problems when you try to pin and stitch the fabric parts together. You can’t just pin along the raw edges on top of each other because they no longer have the same length. And you can imagine as the seam allowance gets wider the difference in length will be more and more.

bra seamallowance

You could mark the original pattern outline on the fabric to know where to stitch. But still it might be difficult to stretch the raw edge of the shorter band cut-out to the wider length of the cup raw edge without getting wrinkles. With this in mind it seems a good idea to keep the seam allowance as narrow as possible.

The best width for home-sewn bras and other lingerie is proven to be 0,75cm (in inches around 5/8).
Narrow enough to keep the length difference workable and enough width to sew without the fabric slipping away.
You’ll have to be very precise about it because the bra pattern parts are quite small compared to other clothes. Before you know it the bra might have another size since the difference between sizes is not that much.

Most people are used to adding a wider seam allowance for their clothes though. Over time your eyes get set to this width and changing to a more narrow seam allowance will be a challenge …
So it’s good use to add the seam allowance to your paper pattern before you cut the fabric.

Measuring 0,75cm all around each pattern part … this might seem a lot of work. But rest assured, there is a neat trick to do the job!
As it happens, when you tape 2 regular pencils together the distance between the 2 points is exactly 0,75cm! 

cuptest nadenvlies

Be sure the pencil points are sharp and at equal length, you might have to take the tape off and sharpen them regularly. But this trick is a real time saver don’t you agree?

And in case you wonder … I often use fleece lining instead of paper to trace bra patterns because it’s sheer enough and won’t tear easily. Very handy as well to sew a quick test for a cup from it, for example to be sure the size is right. 

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