How to Fit a Sewing Pattern

Hey y’all – so in the last post we talked about how to draft a sloper or pattern block for yourself. Today I’m going to show you how to use that sloper to modify patterns you want to sew, because patterns out of the box will pretty much never fit your body perfectly. But that’s why we sew, right? So we can celebrate our uniqueness with equally unique clothing.  I’m using a couple of store bought patterns as examples.

Before we get into which alterations to make, let’s talk about the order of alterations and fitting. It should look approximately like this:

1. Measure yourself. (Be sure you’re doing it correctly and get a handy measurement card in this post)
2. Alter length measurements on the pattern. So if you’re taller or shorter than parts of the pattern, do this first.
3. Alter horizontal measurements, starting with the biggest curves. So if you’re doing a bodice, alter for the bust first. On skirts and pants, alter for the hips first.
4. Make a muslin. This is a tempting step to skip, but you may regret it. The more fitted the garment, the more unlike other garments/patterns you’ve sewn, or important the style lines, the more you’ll regret skipping this step.
5. Adjust fit based on the fit of the muslin.
6. Sew garment.

Alright – let’s see what that looks like on an actual pattern or two! To start with I’m going to use bodice pieces from New Look 6677, a tunic pattern. I’m showing pieces from View A, the light purple one at the top.

The above photo is my actual bodice sloper, without seam allowances, compared to the pattern. I’ve lined them up at the armscye point. You’ll notice a lot of extra lines on my sloper; these are style line references I’ve added to reflect my personal taste. You can safely ignore those; the important part is the overall shape. You can see that the shoulder on this pattern is much too long, even when seam allowances are added, so that would be the first alteration I’d make.

The tunic is supposed to be loose fitting, so for now the width seems OK. But let’s take a closer look below. Comparing the dart on my sloper to the dart on the pattern, we can see that the pattern dart is probably not wide enough. Yes, I have rotated my sloper to compare these, but no matter where the bust dart is placed, a single dart will have the same width on a pattern (see this pin if that concept makes no sense). So, this pattern needs a full bust adjustment if I’m going to wear it.

Now let’s look at the back of the same pattern above – see the immediate problem? The shoulder is too long, yes, but also it’s set too wide. If I sew the pattern as is, this will drag and fall off my narrow shoulders and back, or gape at the back neck. The solution here, since the pattern is cut on a fold, is to take some out of the center back. After shortening the armscye, of course.

Alright, let’s take a look at Simplicity 4958, a gathered empire waist bodice. In this pattern, the fullness of the bust dart is gathered instead of sewn as a dart. Either way, the girls need room.

If you look at the back pattern above, you can see that we’re doing good – the shoulder length is appropriate, and once seam allowances are taken off the shape is very close to my sloper. The difference at the waistline is that the sloper has not had the dart taken out yet.

Now let’s look at the front piece above. Again, so far, so good. BUT, look more closely below:

Once I pinch the gathered area on the pattern piece to match the markings on the lower front, I can see the dart width that was transferred to gathers.

And when I compare that width to the same point on my sloper, the issue emerges – this pattern was drafted for a smaller cup size. Above, my fingers are on the width of the pattern dart that is gathered. And you can see that on my sloper the dart is almost 1/2″ wider at this point than the pattern dart area.

The above image shows (digitally) how I would correct that issue – I would need to slash the pattern and rotate the side seam out to add more width to gather.

Have you had an Aha! moment yet? Even if you never use your sloper to create a design from scratch, it is an invaluably useful tool to help you achieve good fit from patterns drafted by others.

We’re going to cover sleeves and bust adjustments in more depth later, but we can’t possibly cover every fitting issue or technique here. So here are some more fitting resources:

Create the Perfect Fit (affiliate link), which I wrote more about here, has a thorough system of measuring yourself then transferring those measurements to your pattern and altering it. Best of all, it has real life examples at the end. The only caveat (and I’ve shared this with Joi, who I know personally) is that I wish there was a more extensive section on pants fitting. If you prefer a more hands on approach, Joi also teaches fitting classes on Craftsy, here and here (affiliate links)

The Complete Photo Guide to Pattern Alteration (affiliate link), like it’s name, has lots of photos to help you see how to fit garments. Very useful to learn how to see the issues and get the thought process of how to correct them in a muslin.
Sarah Veblen, the author of this book, also has video courses available on PatternReview.

Fitting and Pattern Alteration (affiliate link) is pricier, but that’s because this is basically a dictionary of every fit issue a pattern could have and how to fix it.