FF: Choosing the right size

Sweater knitting and suit shopping have something in common: If a sweater doesn’t fit your shoulders, it will never ever look good. But sweater patterns are sized by the bust, not the shoulders. So how do you ensure a proper fit?

The answer begins with understanding why sweaters are sized by the bust. It actually couldn’t be any other way, because for many constructions it’s unclear what the “shoulder” measurement might be. Set-in sleeves (contiguous or traditional) could size by the distance from sleeve seam to sleeve seam (also known as the sweater’s “cross chest”)…

…but what about yokes? raglans? Sideways all-in-one piece?

Every sweater construction has a bust circumference, though. And here’s the thing:

No matter what your size, all hand knit sweater patterns are created for the same body shape. (Let’s call her “Miss Average”.) Designers use the Craft Yarn Council of America charts, or some close variation on them. The measurements in those charts depict the same shape woman, regardless of size.

Here’s the final kicker:

Miss Average’s bust is a good indicator of her shoulders.

Her bust and shoulders are tightly linked. So when a sweater fits her in the bust, it fits her in the shoulders as well, without any modifications required. This is not true for many, many women.

So how do you pick a size, if not by your bust, when patterns are sized by bust? The answer is your upper torso circumference:


Your torso circumference is the “bust” measurement that closely matches your shoulders. So you should use your upper torso circumference, instead of your full bust, when choosing a “bust circumference” size.

For some women, this won’t make much difference. For busty women, you’ll be choosing a size smaller than your bust (sometimes by a fair amount). For broad-shouldered, smaller-busted women, you’ll be choosing a size larger than your bust. When choosing a size, you have three basic fit options. Let’s look at an example of each, on my frame. For reference, my upper torso circumference is 38” and my full bust is 41”.

  • A snug fit will fit fairly close to your body. The armholes will be a bit smaller, and the shoulder fit more figure-conscious. Achieve it by selecting a bust size 0 – 1” larger than your upper torso circumference. Here’s what it looks like, in a sweater:


    (This sweater is a size 38”, exactly matching my 38” torso circumference.)

  • An average fit is just that: Average. It’s comfortable, will fit your shoulders but not super-tightly. Achieve it by selecting a bust size 1 – 2” larger than your upper torso circumference. Here’s what it looks like, in a sweater:


    (This sweater is a size 39.5”, 1.5” larger than my torso circumference.)

  • A relaxed fit will still fit (the shoulder seams won’t be down on your arms), but it will give you plenty of space in the armholes and chest for a few layers. Achieve it by selecting a bust size 2 – 3” larger than your upper torso circumference. Here’s what it looks like, in a sweater:


    (This sweater is a size 40.5”, 2.5” larger than my torso circumference.)

To get a great fit in your shoulders, here’s how to select a sweater size:

  1. First, take your own upper torso circumference. Place the measuring tape as high in your armpit as it will go, pull it pretty snugly, put your arms to your side, and breathe normally.
  2. Next, decide on the fit you want. Average? Snug? Relaxed? Add the appropriate amount of ease to your upper torso circumference.
  3. Look at the finished bust circumferences of the pattern. Find the one closest to your result from Step 2. This is your base size.
  4. Compare the other measurements for that base size against your own body to determine what modifications you’ll need to make. For example, if everything works aside from the full bust vs. your own full bust (because you’re a busty figure), you will add an inch or more of bust darts to the front of the sweater. If everything works aside from the hip, because you have larger or smaller hips, that’s an adjustment you can make to the cast-on stitches. And so on.

And there you have it! If you choose your sweater size in this way, you’ll achieve a great fit in the shoulders, and be well on your way to a fantastically-fitting sweater. You might need to make some modifications, but by and large it’s far easier to tweak the waist and hip fit, rather than to try and fix shoulders that are fundamentally wrong.

How close in size are your favorite sweaters to your upper torso circumference? Had any sweater disasters? Let’s talk in the comments! And happy Friday!

33 thoughts on “FF: Choosing the right size

  1. Your book and Craftsy course have changed the way I choose the size of cardigan or jumper. It has also helped with sewing dresses. Revelatory!!!

  2. I’m loving these regular mini-lessons, and this one comes at just the right time: I’m planning my next sweater now!

  3. Could you show examples where it is the other way? Where the upper torso is larger than the bust?

    1. My BFF is shaped like this. Very slender but with strong! swimmer’s shoulders. She needs an 8 to almost accommodate her shoulders & lats and a 4 to fit her torso. It’s making helping her find anything to fit well(or making her a flattering sweater) very frustrating.

    2. Yes, this is a great idea! It will take me a little bit to collect people and get the photos taken, but I’d love to do this.

      1. My daughter is a swimmer too … would love to see how you figure this one where upper torso larger than bust.

  4. I love these mini lessons. I’ve purchased your Craftsy course, but haven’t watched it all the way through yet. I have a question on your examples here…in the 3rd example is the finished sweater measurement .5 inch smaller than your actual bust measurement, yet it is still a relaxed fit? Or did you start with size 40.5 sweater and increased for the bust?

    1. Great question. I added in a small amount of short rows, but no width. So there is a little bit of negative ease in the bust. Personally, I find that fit in the fullest part of my bust doesn’t really affect the overall “fit” of the sweater as much as shoulder / waist / hip fit does.

  5. My favourites these days tend to be a bit roomier with less waist shaping.

    It is good to see the differences in ease above, really makes it clearer how to plan new knits…thanks Amy!

  6. That’s very helpfull lesson.Thanks.

  7. A great mini-lesson reminder for all of us, and particularly for those who have not yet leaped on the FF bandwagon!!!

    My Firefly yarn has arrived; time to re-take some measurements and start my Nantasket.

  8. When patterns are written, do they include any ease at all? Is there a standard for pattern writers? I ask because following your instructions – Thanks! I love them! – my upper torso measurement is 37 so + 1-2 gives me 39-40 for proper size for medium ease. The closest size for the pattern I want to knit is 40 1/2 but does this include ease already? Thanks so much, Amy.

    1. Great question! I don’t know the answer but I’m sure someone does – at least I hope so.

      AND – “bust dart” was confusing me because in sewing a “dart” pinches in the fabric but in knitting a bust dart, we are adding stitches – right?

      1. And yes, Mary, you’re exactly right. Maybe we should call them “anti darts”? πŸ™‚

    2. Some patterns include ease in the main sizing and some don’t. Any time the pattern says “Finished measurements” or “Finished bust circumference”, those are the actual finished measurements with no ease included. If the instructions say “To fit size”, you’re better off looking at the actual pattern schematic. Hope this helps!

  9. I have purchased your Craftsy course and book but am just getting started going through them. This mini-lesson really hit home though. I am extremely busty and I can’t tell you how many ill-fitting sweaters I’ve knitted for myself :-(. When I go by bust size to determine sweater size everything else just seems to be so far off! Thank you so much for sharing this — I’m feeling more optimistic about my next sweater already.

  10. Thanks for this post Amy. I have broad shoulders and this looks like a much better approach than doing what I have done and making the sweater a much bigger size, especially if I want a sweater that is a bit more fitted. I’m going to start a new sweater and will try this approach to determine the size.

  11. This is huge for me. I have a big (at least big-ish) bust and very narrow shoulders. Deciding on a sweater by bust size will always ensure an ill-fitting sweater. Love love love this!

  12. This really works. I just finished my very first, but not last F2F sweater and it’s the first sweater that has fit me well. I am thrilled.

    I love Amy’s book and her Craftsy class which have changed my attitude about my own shape. Now I know how to make adjustments for flattering sweaters. Thanks Amy!!

    1. (heart) So thrilled you like your sweater!

  13. Thanks Amy. This lesson is going to change how I pick a size for my next sweater. Showing examples of “fit” is SO helpful.

  14. The “which size is correct?” question has been keeping me from even attempting to knit a sweater because I could never find a good explanation for amounts of ease corresponding to resulting fit. This is perfect! Thank you, Amy!

  15. Amy, you are the “Bomb”! This will make it so much easier to fit me now. :). Thanks for the tips. You have a reader for life!!!

  16. I heart you and where have you been all my life! Thank you so very much for recognizing that women are not cut from a cookie cutter and that we need to invest our knitting time into garments that make us proud and look amazing πŸ™‚

  17. Thank you! This is soooo useful.

  18. I really love all the work you put into helping women feel comfortable in their clothes. Nothing worse than finishing a sweater and not feeling good about yourself in it!

  19. Great post! I love the examples, they really help me “get it” πŸ˜‰

  20. You are such a genius at breaking these concepts down. Genius! Thank you so much.

  21. I add to the comments on what a GREAT mini lesson this is!! I too have purchased book and Craftsy class and just beginning to go through it to change my knitting forever!!
    one burning question–the middle photo of you in the blue tweed pullover sweater–what pattern is that!!!

    1. The brown tweed in the last photo is “Salina”, by Kim Hargreaves. The more bluish-gray pullover with the Henley neck is my own “Sapwood” from Twist Collective. Hope this helps! πŸ™‚

  22. thank you!!! it does help! C

  23. My sweater paradigm has just been shifted! Thanks for the post.

  24. My mind is literally blown! I didn’t know it was this easy to get a proper fit for a sweater pattern. I cannot thank you enough. I struggle with patterns fitting due to how β€œbusty” I am. I will definitely using this for my next pattern! Thanks again

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