FF: Why Bottom-Up

I hope that everyone who celebrates had a fabulous 4th of July. (I sure did!)

For this Fashion Friday, I wanted to talk a little bit about why the first release of CustomFit. I’ve gotten a few comments already about top-down raglans and whether CustomFit will produce them:

I knit top-down raglans. Will CustomFit work for me?
CustomFit works for everyone. But although we plan to change this in the future, it currently produces bottom-up patterns. You can choose between a pieced or (mostly) seamless construction. (Mostly seamless means the sweater is knit in the round to the armholes, then back-and-forth to the shoulders. The tops of the shoulders are seamed, and sleeves are worked top-down in the round. This produces a set-in-sleeve fit with only a few inches of simple seaming.)

Since I get a round of groans in every class when I suggest knitting a “pieced” sweater (whether you sew in the sleeves or pick them up and work top-down), I am absolutely, positively aware of how unpopular this garment construction is. A whole new generation of garment knitters have been brought into the sweater knitting fold with top-down raglans, and are loathe to switch.

Why that is, I don’t know exactly? But I think it probably has to do with the set-in construction seeming… daunting. There’s the seaming, maybe. Or short row sleeve caps, which are not exactly a simple-seeming alternative. There’s the apparent unpredictability of all of it: You don’t see whether your sweater works out until it’s finished. And emotionally, I think set-in-sleeves just feel so fussy and fashiony. What could be more attractive than the exact opposite of that?

I suspect that to anyone who was not brought to knitting specifically as a way to make clothing, it just seems… hard. Pointlessly hard.

…well, hard is relative, but it’s certainly not pointless. There are actually reasons for this fussy madness, and they relate directly to what CustomFit is trying to do. So let’s talk about the reason that trumps all others. I’ll start by talking about pieced sweaters, and revisit my “mostly seamless” option at the end.

A pieced, set-in-sleeve construction is the easiest to modify across all body types.

The importance of this cannot be overstated. If I want to produce software that will result in a perfectly-fitting garment for all women who come to use it, I must (must) start with a pieced construction. Here’s why. A well-fitting sweater will fit the wearer in the bust, cross-chest/shoulders, and sleeves. In a pieced construction, you have many degrees of freedom to achieve a good fit in those 3 areas fairly independently. I’ve marked them in green, here:


  1. Fitting the bust can be done by measuring it and multiplying it by your stitch gauge.
  2. Fitting the cross-chest can be easily achieved no matter how widely different the shoulders and bust are, because you can bind off many stitches if necessary.
  3. The bicep may be calculated independently of the shoulders and/or bust.

All of this is possible because the sleeve cap is where they all come together, and it can be solved for (largely) independently. The length of the bit marked in red must be the same length as the total armhole length (front and back) on the body. But while there are a few restrictions on how to shape the cap, as a designer (or a piece of software) you have lots of opportunity to make that length long or short, to match the body. And as long as they are the same length, the armhole and the sleeve cap can be done entirely differently.

Let’s contrast that with a typical top-down raglan construction:


It’s not that these sweaters are bad. They’re not. In fact, for those bodies they fit well, they’re pretty fantastic! The problem is that the red line here represents your opportunity, as a designer, to change the bust, cross-chest, and bicep–and you can’t fiddle with one without affecting the others.

There are a few things you can do. If you need a deeper armhole, you can increase every 3rd row instead of every other row. You could make the rate of body increase (the inside of the red line) slightly different than the rate of the sleeve increase (the outside of the red line)… but only slightly different. Try to get too fancy, and your fabric is going to pucker. Fundamentally, the way you make the bust larger is to make the sleeves larger and the armhole deeper. Period.

So if top-down raglans work for you, that’s completely and utterly awesome. But know that they don’t work (can’t work, even) for a large class of bodies. CustomFit has to work for every body. So it will start with a set-in sleeve construction, to give me the freedom I need to fit any woman’s shoulders, bust, and arms perfectly.

Thanks for sticking with me this far! A couple of more points.

  • A sweater that’s worn is always better than a sweater that sits in a basket awaiting seaming. This is why I’m offering the mostly seamless construction option. The math is fundamentally the same, and I have the same amount of freedom between those three crucial body points. But when you’re done with the sweater, you’re done! No seaming required except in the middle, and then only for the shoulders.
  • If you’re reluctant to knit a sweater this way because there is no security blanket of trying on the sweater as you go, fear not. CustomFit largely eliminates the need for that fear. It takes your body, and your gauge, and does all of the math for you. This results in a perfect fit without a single try-on.

I know that last one is hard to believe, because we’ve all gotten it so very wrong on at least one occasion. (Me too, by the way!). But I offer up the following as evidence:


This is a version of The Flutter Pullover, from the bookbut with a different neckline to better accommodate my body’s needs. It fits pretty well, right?



Here’s the cool thing about this sweater: I didn’t knit it. I had a few samples of book sweaters worked up to wear to classes and events, and this was one of them. Essentially, I gave my awesome sample knitter my measurements and gauge, and off she went. No try-ons, no eyeballing as I went.

It can work, I promise. And I hope that even if up until now you’ve been a die-hard top-down-raglan knitter, you’ll give another construction style a try.

50 thoughts on “FF: Why Bottom-Up

  1. I am a big fan of seamed construction – it’s how I learned to make sweaters in the first place! I am always leery of the “mostly seamless” construction because my “in the round” gauge and “back and forth” gauge tend to be pretty different (I think I purl more loosly than I knit). Have you considered using different gauges for the different areas of those sweaters?

    1. Thanks for the comment, Suzyn! My only worry with that approach would be that you’d need to decrease stitches along the “switch” line. Maybe an alternative is that when you swatch, figure out what needle size you’ll need to use for both flat and in-the-round bits?

      1. And that’s why I’ve been known to “flatten out” patterns with portions in the round!

  2. Sigh. It makes sense. I just HATE the prospect of all the purling. I would rather knit in the round if it was possible – but you make good points as to why it isn’t in these cased 🙁

    1. I hear you, Kivy! You can definitely minimize the purling with the “mostly seamless” construction, but it doesn’t go away entirely.

  3. * cases even…

  4. Before I knitted, I sewed, and I still do sew when I can force myself to carve out time for it. So my background trained me that first you have pieces, then you put them together and have a garment. Although I do knit stranded-yoke traditional sweaters, the idea of working top down and producing the garment all in one go feels foreign to me. I’d much rather make pieces and assemble!

  5. Perhaps I am an old dinosour but I HATE HATE HATE top down patterns – they make no sense to me and I don’t think they are faster or easiers – I avoid them like the plague. I have knit for decades and know enough about a pattern that if it is top down and I LOVE it enough, I can work it from the bottom up so I do. Something else I hate about top down with raglans is that in my opinion the decreasing of the stitches never look as gorgeous as they down when knitting from the bottom up. Just my opinion and to each their own.

  6. As E says, a knowledge of dressmaking is a huge help when understanding seamed construction. You learn about alterations there too if you do enough of it, and that also is a help. (And as a woman 5′ tall with broad shoulders and a large bust, I have a deep-seated antipathy for anything raglan. YMMV.)

    1. I definitely agree with you and E on how helpful a sewing background is. But I do think it’s interesting to watch a whole generation of knitters “grow up” without that, too! It’s always exciting to be able to investigate and approach new points of view, and blend them into our existing ones. (E.g. the contiguous top-down set-in-sleeve approach, which I’m not super well-versed in.)

  7. THAT is exactly the neckline I have been hunting for. In fact, I am in the process of spinning the yarn to make a sweater right now. Where may I find a pattern? Is it in the book that I have ordered?

    1. Aww, thanks Ann! It’s my own modification to the neckline in the book (same sweater, I dropped the neckline and fiddled with it). I’ll be sure to do a proper post on the sweater soon!

      1. Amy, you also narrowed the sleeves too, right. I really liked the pattern in the book, but wasn’t crazy about the wider at the bottom sleeves.

        1. Actually, my arms are just on the larger side! 🙂 I didn’t make any changes to the sleees; but someone with more slender arms who wanted a similar apparent shape *would* do so. Hope this helps!

  8. This makes perfect sense, and I look forward to knitting one of your sweaters. Raglans only work on me if they have some kind of closure, otherwise they flap open unattractively at the top. I learned the hard way!

    1. Ugh, me too! They collect in my armpits. 🙁

  9. Thanks for posting this. It is really helpful on understanding the benefits of knitting in different ways. I have not knit my own sweater yet but wanted find a pattern that is very simple to make.

    1. My pleasure! I try to make all of my designs (with a couple of exceptions) very easy to modify and suitable for a first-time knitter. Ysolda Teague’s blank canvas is another good choice for a plain first sweater. Hope this helps!

      1. Thank you for suggesting a pattern Amy. I do hope to knit one of yours, maybe with some minor modifications like lengthen the sleeves. They are beautiful and I can see myself in them.

  10. Just wanted to mention that there are now several methods for knitting set-in sleeve sweaters topdown–it’s not just for raglan!

    1. Yes, Tracy–thank you! I’m not as experienced with them but would love your thoughts on how one might adjust e.g. the bicep without affecting the cross chest / bust. I bet it can be done?

  11. i must agree with Tracy on this : what about set-in sleeves top down ? round yoke top down ? and also sadle shoulders top down ? I must say that you you compare bottom up to only raglan top down, it’s a bit biased 😉

    You can have the exact same perfect fit with top down set in sleeves 🙂

    1. Absolutely, Elise, this is a great point, and as I’d said to Tracy while you were typing (:)) I’d love to talk more about it. The comments I’ve gotten so far focused explicitly on top-down raglans, but I’d love to explore other constructions and their limits / ease of mod.

      I think any “all-in-one” might be at a slight disadvantage the *first* time you do a mod, since you’ve got to tackle the whole thing at once instead of in more easily digestible chunks… but a non-raglan definitely won’t be as limited in terms of the cross-chest/bust/bicep ratio.

      Have you successfully modified sweaters with these other top-down constructions? I’d love to hear your experience!

  12. A key point in ‘sweater happiness’ was learning to sew a nice-looking seam. It is worth the time. Second, of course, was Fit to Flatter…and it really does.

  13. I think there are many advantages to seamed knitting and I think you are brave to try to convince knitters that it is the best way. So many knitters do not come from knitting through sewing and the idea of sewing anything is scary.
    Many people’s finishing skills are not up to par, so they can knit a beautiful pieced sweater and then put it together and it doesn’t look good.
    Most of my designs are relatively seamless for those reasons, but some designs just beg for seams and set in sleeves. I do love the top down set in sleeve because sewing in a sleeve is quite tricky for many knitters.

  14. Amy, I am totally on your set-in sleeve bandwagon. One thing I never understood about the top-down, try-on-as-you-go sweater: how do you account for washed gauge? Most of the yarn I’ve knit with changes gauge when blocked, with the rare exception. Am I the only one washing my sweaters, I wonder? Also, set-in sleeves are definitely more flattering on me, and most people, I think. Thank you for all the great work you do!

    1. I think that’s a great question, Leah. Probably, like anything, it varies from knitter to knitter. Umpteen sweaters in, I could probably account for a gauge in a top-down sweater the same way I do in my pieced ones, which is largely by feel and memory of how the swatch felt / measured before and after washing. But I’d be interested if someone else has an opinion?

    2. I don’t know if this is unusual, but when I’m making a top down garment, I still knit a swatch, wash the swatch as I intend to wash the sweater, and dry it the way I intend to dry the sweater. That way, no surprises! 🙂

  15. Amy, I would like your thoughts on the ‘lifetime’ of a sweater when knit in pieces from the bottom up versus raglan or other top down construction.

    I have knit a few top down sweaters (raglan, yoke, contiguous) and a couple of bottom up ‘pieced’ sweaters. One designer had a comment that pieced sweaters wore better and lasted longer than top down ‘seamless’ sweaters. It was her thought that top down ‘seamless’ sweaters stretched out of shape quickly and became old before their time. My personal experience is that top down raglans are guilty of stretching a lot every time you wear them. I haven’t had the same result with yoke type sweaters and my contiguous sweaters are too new to make any comment. However, sweaters with dropped shoulders also stretched a lot and they are pieced whereas normal pieced sweaters (with set in sleeves, shoulder seams and side seams) don’t seem to sag as much. I know that a lot of the sagging is attributable to the weight of the sweater yarn. I wonder what your thoughts are on this subject.

    Thank you.

    1. I would think that drop-shoulders (particularly if a 3-needle bind-off was used) and raglans, at least, would have a similar problem sagging-wise. In both cases, the weight of the sweater is resting on a less-structural bit (the middle of St st for the raglan, and well above the structural sleeve seam in the drop-shoulder case). The looseness of most drop-shoulder styles would come into play too I bet. Yokes rest the weight evenly over the whole yoked piece, and set-ins are fairly snug with lots of structural seams near the weight-bearing point.

  16. I’m fascinated by this post and the discussion in the comments! I suppose I am part of the “new generation” who leans away from pieced sweaters sometimes, but in my own experience that’s not because seaming is hard or unpleasant (I love seaming and finishing work in general), or because you can’t try on as you go, but rather just a preference for a particular garment style and look. What I mean is, I wonder if some knitters are choosing more top down styles because they find those garments stylish, rather than because they’re perceived to be easier to make. Many pieced garments have a more formal look – maybe casual style is preferred?

    Of course what looks good on an individual body will always work best (and some people’s bodies aren’t ideally matched with any kind of top down sweater), but it just doesn’t seem to me like it’s about fear or unwillingness to try things among knitters. People do choose to buy and wear garments based on generational style as well as “what looks good on a body” (see ubiquitous wearing of skinny pants across all kinds of body types! 🙂 )

    1. Sarah, I think this is a wonderful point.

  17. Wow. You look beautiful in that sweater, and I love the colour! I don’t have an opinion yet, on sweater construction, but I appreciate all of the extra information you’re providing. Thanks for all the great, informative posts.

  18. I have fairly narrow, sloping shoulders and a short waist. This means that raglan sleeve sweaters end up with an unattractive, almost ‘triangular’ appearance on me. Dolman sleeves are even worse!
    Set-in sleeves produce a much nicer rectangular line. (It’s one of the reasons I like so many of your patterns.)
    Knitting from the bottom-up also seems to be an incentive to me, as the rows get shorter and shorter as you near the end!

  19. I love love love set in sleeves, all about set in sleeves and plan on only knitting set in sleeves from now on.

    They fit and look the best on me and to me not harder than any other sleeve.

    I have been doing top down for a while so I am looking forward to going back to bottom up to see fit wise how it will work and fit.

    So excited about this software and can’t wait to use it to finally get sweaters that fit me and look fab on.

  20. Lovelovelove this sweater on you. So much that I’ll consider it for me, too! (Have to finish Petrea first…)

    I asked this on Ravelry, but I will here as well: What yarn did you use? I adore the color.

    1. Thanks so much! It’s the recommended yarn, Sweet Georgia Merino Silk Fine, in “Black Plum”.

  21. Love this post! I wholeheartedly agree that seamed sweaters result in better fit (they also wear better, IMO). So interesting to read the comments regarding raglans and body type because they do not fit me at all – I would say that I have a proportional figure with a smaller than average bust and “coat hanger” shoulders – “top down in the round” never fit me!
    I have just frogged a bottom up seamless one that I loved the look of – but I inevitably find that when I knit one piece sweaters, I have issues with shoulder pain. Not the fit of the sweater so much as the weight of dragging it around. If I eventually do knit that pattern, I will have to convert it to pieces. Planning to knit Jackaroo instead!

  22. I started out knitting sweaters top-down raglan, but am one of the people that it just doesn’t flatter. I think I’ve converted over to the bottom-up construction but mostly seamlessly, with set-in-sleeves picked up from around the armhole and knit down in the round. I get to block and check the shoulder fit before I do the sleeves which is the part that has been the most ill-fitting for me in the past. AND I still have a mostly seamless garment AND I can still check sleeve length as I go. I’m excited to see how customfit comes out!

  23. I have knit sweaters every way except round- yoke, and raglans don’t fit me in a way that is flattering. Also, the miles of stockinette stitch after the armholes can be dull to knit.
    I don’t like seaming armholes though. I did it once, and it turned out okay, but my last attempt was a nightmare- the unseamed sweater still mocks me. I tried and tried to make it work- a really terrible experience. I should go back and knit them from the top with short rows- which I actually find to be really fun!
    I also tried bottom-up, set-in-the-sleeves-as-you-go, as described by Jared Flood in Vogue a few years ago. It worked the first time, but the second time my row and stitch gauges were too far off and now I have an otherwise stunning sweater with a puckery shoulder. Annoying- and because of the construction very hard to fix.
    So, I’m looking at pieced construction again, despite having been burned. I do agree with Sarah that often those sweaters have a more formal look, which when assembling a work wardrobe can be a good thing.
    I really enjoy the discussions of sweater construction and find them helpful as I think about the modifications I make- frequently turning pieced sweaters into knit in the round. For a long time my flat knitting had a corrugated look because of the gauge difference between knitting a purling. Ysolda’s book “Little Red In the City” helped me solve that problem though, so I have more freedom in my knitting. I agree with your suggestion to find the same gauge knitting flat and in the round by switching needle sizes- that has worked wonderfully for me.
    Thanks again for the discussion and for your commitment to beautiful, well-fitting sweaters for ALL knitters!

  24. I just found this site tonight so I haven’t explored everything that is being discussed here, but I do agree that pieced sweaters just look nicer. I’ve only been knitting for about 6 years, so I probably do fall into this new generation of knitters.

    My first sweater was a bottom up raglan knit in the round. I picked it because I thought it would be easy for a first sweater and it was. The sweater looked nice while it was being knit and it looked nice blocked, but after an hour or so of wearing, it didn’t hold it’s form at all. It seemed to just get baggier and baggier. I think if you have less than perfect posture and/or a large bust, there’s no way a seamless knit will stay where it should. Seams create structure.

    I think ease of construction shouldn’t be the primary concern when choosing a pattern. What does it matter how easy it was to knit if it doesn’t look awesome when you’re done? Knitting a sweater is a good amount of work and I would rather take a little extra time and effort to have something nice than waste ALL that time on something that’s just mediocre at best.

  25. I can’t bear the thought of knitting and seaming pieces together.. Brings me out in a sweat…

    Top down all the way for me.. I like the way you can try on as you go and modify if necessary.. I like raglan sleeves but I also think the top down set in sleeve look great and give a better arm finish than raglan.. This will be my next sweater project.

    Sorry Amy despite all the good points you put forward for working in pieces and seaming hasn’t won me over.

    The couple of times I’ve worked seamed pieces it all went wrong.. And the thought of wasting all that time knitting lovely tops only for them not to fit and sit gather dust unworn and unloved depresses me..

    1. I just wanted to say that I wholeheartedly support you doing what works for you! CustomFit will absolutely eventually support at least one top-down construction. I just thought it would be interesting to share with everyone why CF started off the way it did.

      I’m absolutely a fan of sweaters you love to wear, HOWEVER you go about getting them!

  26. Pick #3!

  27. I think #3 is particularly beautiful, a shade that suits so many.

  28. […] are advantages and disadvantages to each approach, with proponents on either side. Amy Herzog is a big fan of bottom-up sweater construction. While Karen Templar is a defender of top-down sweater […]

  29. Which of Amy’s sweater patterns are “nearly seamless”? I am usually a top down raglan sleeve in the round knitter, but I would like to try one of her custom fit patterns. The “nearly seamless” would be the best one for me to start with.

    Thank you!

    1. Hi Susan! I have a couple of patterns are are worked in one piece (either side-to-side or hem-to-hem), and then seamed under the arms. Curlew, Small Point, Easton, and my Rigging Sweatshirt and Blaze Cardigan from You Can Knit That, are all worked in this way.

      You can also work most any set-in sleeve pattern *nearly* seamlessly; it’s been on my list to write a tutorial about this! I’ll move it up in the queue. 🙂

  30. I think there’s another possible advantage to knitting in pieces – ease of making alterations/reknitting individual pieces. If you finish knitting but then find you need to fix something, it can be easier if the item is knitted in pieces. For example, if the bust shaping isn’t right, you only need to unravel the front sweater piece. If the sleeve is too wide at the bicep, you only have to unravel the sleeve cap and the top of the sleeve. In one-piece construction you might have to unravel a lot more to get to the bit you need to fix.

    Okay, if you measure and swatch carefully, you might not need to fix things after the fact. But you might change your mind on a style matter, like “I want a different cable on the sleeve” or “I want a crew neck, not a v-neck”.

  31. I am the naysayer here but really look forward to top down options in Custom Fit. I avoid seamed sweaters knit in pieces and my knitting life and sweaters re better for it. I have a huge preference for top-down sweaters knit in one piece but avoid raglans and drop shoulders as they are unflattering. I knit my set-in sleeves top down using the Elizabeth Doherty method (a modification of Barbara Walker). I put 2 purl stitches to mark a faux side seam and tell myself if the finished garment needs a seam I will add a line of slip stitch crochet inside along the seam line (but I have never needed to do this). I pick up and knit down on the sleeves as soon as I have finished the sweater to the armholes so that I don’t have the full weight of the sweater hanging off my needles when I knit the sleeves.
    I like to try on as I go and will make adjustments to style, colour etc. as I go along. Basically I never knit a sweater pattern exactly as written (the blind faith and conformity that Custom Fit currently requires) but change as I go. For example, I am knitting the Comfort Fade Cardi by Andrea Mowry but have already decided to make only 3 colours with no significant colour changes below the waist. I will make it in one piece with set in sleeves picked up and knit down in the round. I will likely change the neck drop and colour changes when I try it on as I go. As washed and blocked stitch gauge affects length measurements I take that into account as I try it on (in some cases assume it will be an inch or more longer than where I am trying it on). I enjoy seeing the sweater come together in one piece as I go rather than leaving all the surprises to the end.

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