How to do a Full Bicep Adjustment

A full bicep adjustment is one of the most simple sewing pattern adjustments to make, and is an essential skill in your garment sewing arsenal. Click through to learn how to adjust a basic sleeve pattern.

Often, when toiling a new sewing pattern, you’ll find a part of the pattern that doesn’t fit you quite right and could do with an adjustment.

For me, I often find that sleeves are too tight. Until now, I’ve been grading out from the sleeve head to a larger size, and/or using a smaller seam allowance to give me a little more space.

However, this week I met a sewing pattern that needed more than grading and smaller seam allowances. The By Hand London Hannah is a fabulous pattern. I love it. It fits me perfectly everywhere but the sleeves. So, how do I fix it? Answer: A Full Bicep Adjustment.

A Full Bicep Adjustment makes the sleeve bigger, giving you more room, without making the sleeve head bigger or lengthening the sleeve unnecessarily.

It’s a very simple adjustment to make, following a similar technique to a Full or Small Bust Adjustment, and will give you another incredibly useful skill to add to your sewing arsenal.

So, how do I do a Full Bicep Adjustment?

First, trace your sleeve pattern onto a piece of paper, drawing in any key pattern marks and your seam allowance.

Next, draw a line from the very centre of the sleeve head (from the seam allowance line) to the bottom of the pattern. Then, draw a small circle where the seam allowance meets the new vertical line, and snip into the seam allowance, being careful not to snip the circle. We want to create a hinge, not cut right through it.

Next, draw a horizonal line from fullest part of the sleeve, where the underarm and sleeve head meets (again, from the seam allowance). Draw small circles at both ends of the line, at the seam allowances. Make the same snips you did to the sleeve head.

Then, from the bottom of the pattern to the seam allowance, cut up the vertical line, then cut along the horizonal lines to the seam allowances. From here we can hinge the pattern to make our adjustment.

But first you need to determine how much extra room you need. Measure your bicep 2-3″ below your armpit, adding the ease that you require (be sure to add the ease you need, don’t just take your exact bicep measurement). Remember, you don’t need to account for seam allowance here as we never removed it from the pattern.

Next, measure your pattern piece horizontally from seam allowance to seam allowance and determine the difference from your measurements. This difference is how much you will need to hinge the pattern.

Place your now hinging sleeve pattern onto a new piece of paper large enough to handle the extra inches/cms we’re going to add. Then, hinge open the vertical line by how much you wish to add. You’ll notice that the horizonal lines will overlap here.

Tape down the width that you’ve added, then true up the bottom of the sleeve pattern by drawing a straight line across, then redraw the curve at the sleeve head as necessary.

Trim away the excess paper, tape everything down securely and you’re good to go. At this point I’d recommend making a toile/muslin from cheaper fabric to check the fit before using any precious fabric.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s