I have been procrastinating the start of my Knip Mode skirt a la Cidell by researching FBAs (Full Bust Adjustments).  There is a plethora of information out there on the interwebs and frankly, I’m drowning.  Each tutorial I read brings up more questions than answers for me.  (Is this sounding like a trend to you? Because it is to me.)  Karen’s probably going to say that I am thinking about it too much.  I have found two methods so far that are promising (i.e., I understand them).   But I still have some questions.  

Let me back up a bit and tell you how I came to the conclusion that I need to add an FBA to my tops.  Remember when I started my TNT (tried and true patterns) project a couple of months ago with the failed pencil skirt and drape neck top disaster

NL 6901 Muslin


NL 6807 Muslin


My teacher Thea saved the day with two of the muslins.  I really like the fit of my pencil skirt now (please don’t notice that it hasn’t yet been put into production yet though).  Tuesday night I tried on my NL 6901 muslin again and the pendulum has swung back into the hate territory.  This muslin is not salvageable.  Since I had to cut off the binding due to not being able to rip the stitches out, the neckline is too huge.  Overall the size is too big, yet too small in the bust.  The armscyes are huge.  I think I need to go down one maybe two sizes to get this to fit correctly.  However, since the bust area is already too small in this size, I now know that I need to do my first ever FBA.  

Which leads me to all the research I’ve been doing this week on FBAs.  I’ve found tons of tutorials for FBAs using darts for woven tops.  I even found a tutorial for wrap bodices.  Specifically I need an FBA tute that does NOT utilize a dart and is good for knits.  I found a cheater one on Debbie Cook’s site that I think my work, but I am wondering if it would make my armscye too big.  Hmmmm…  I guess I just have to put the big girl panties on and try it, right?  *big breath* 

One question that needs to be answered first though is, how much of an FBA should I make?  Most patterns are drafted for B cups.  I am well into C cup territory.  In all my research, I have yet to find the amount per cup you should add for going up one size.   Do any of you, my lovely readers, have any suggestions as to where I can find this information?  My newbie sewist intuition is 1 inch, but who knows, I could be off by a mile.  

Anyway, that’s what I’ve been up to.  What have you been up to?

9 responses to “Researching

  1. I believe that the amount is 1″ for a C cup, 2″ for D, etc. as the patterns are drafted for B cups and each cup size above it adds an inch. I’ve never made the adjustment (I’m a B) so I can’t say if that’s the official answer, but I’m pretty sure it is. I have a question though – are you sewing the size that corresponds to your high bust (above bust, under arms) measurement? Because depending on how that measurement relates to your full bust, you may need to make a different adjustment amount. If that measurement is 3″ different, you’d make the 1″ adjustment, but if it’s more of a difference, I believe you would increase the adjustment accordingly.

  2. As a full cupped gal (I’m a DD most days) I’ve made a few FBAs, and I have to say that the amount you add can vary, depending on the result you want. I base my pattern size on my high bust, then either tissue fit the pattern to determine how many inches I need to add to get CF to come to my actual CF (over the girls!), or I flat pattern measure, then figure out how much I need to add to get the pattern measurement to add up to mine (don’t forget to add ease if you do it this way). Also, remember that you are altering one side of a pair, so add HALF of the total amount you need to increase. I always remember that I have two boobs, so each one needs half. Good luck!! It takes some practice, but you will be so much happier with the fit of your clothing once you have added this skill to your arsenal.
    Happy sewing!

  3. I’m a big fan of “Fit for Real People” and I have to do FBA’s ALL the time. It’s great for the visual learner (like me) who doesn’t have the time/money/patience for doing a muslin. FFRP has saved my bacon MANY times. A large majority of your fitting adjustments are done on the pattern and then you tweak final adjustments in your fashion fabric. They walk you through every step and have TONS of illustrations so you never have to second-guess if your final piece is going to fit. You KNOW it will. The FFRP method took all the guesswork out of fitting for me. I highly recommend it. It changed my (sewing) life.

  4. I agree with Darci. Get the book ‘Fit for Real People’. It’s great and will be really helpful. I use their method of FBA all the time.

  5. I agree with Katie, you need to determine the extra amount needed on a case by case basis as each pattern will be different based on the ease in the pattern. Unfortunately the pattern companies do not seem to work to a standard. Also going by cup size alone doesn’t work for me. I am a size D cup in a bra but if I go by the high bust versus full bust measurement in patterns I am only a B as I have a wide back, but a narrow ribcage by comparison.

  6. I think a 1 inch adjustment is WAY TOO BIG for you. I’m in the G to J cup range and I use 1 3/4 which fits me perfectly. I think I’d make a 1/2 inch adjustment if you want a dart.

    But concerning knits – which is practically all I sew for tops due to the large bust….I need stretch…. if I only needed to increase a knit one size, I’d NOT add a sewn dart. I’d add a “bump” to the pattern. I do this with a tried and true pattern WITH my FBA (I don’t need a full 1 3/4 inch dart if I use the bump) and it turns out beautifully.

    Here’s what I’d try:
    1. On your pattern, at the side seam, mark your armhole’s seam line.
    2. From that seam line, draw a slight outward curve – cup your hand and follow that shape of curve and that length (about 4 or 5 inches long). But do NOT follow the depth of your hand- make it only about an inch to the widest part. Meld the bottom of the curve into your existing seamline.
    3. Mimic the curve on the back pattern piece.

    This should be all you’ll need for your bust on a knit. I read this somewhere and have used it to reduce the amount of dart I need.

    Another thing about darts and knits: sew the shoulder seams first, then slip over your head. Your dart placement will vary by knit type. So cut your side seams extra wide to begin with and only mark your curve placement after trying on the knit. Some knits are heavy and weigh down.


  7. well you’ve already received some excellent advice but I’ll confirm what others have already said – on a woven you can’t beat FFRP’s methodology.

    With a knit, I find it differs according to whether it’s one way or two way stretch or if it’s a very stretchy or just a little stretchy (that amount of lycra or elastane).

    I also struggle – you are not alone!

    However, I’m not sure if there is an exact amount you need to add by cup size – if the amount went up in 1 inch increments from a B cup I’d be adding 6 inches! I only need to do a 2 inch FBA, so I’m guessing there’s more to it than that.

    very best of luck.

  8. As with what Mary Nanna said, you’ve received some great advice so far but I completely agree with the comment that 1 inch per cup size sounds huge… by that logic I’d need to add 4″ and whenever I’ve done a FBA I’ve added less than 2″ (I used the tissue fit and work out how far away the tissue is from your CF method when I did one).

  9. There’s a 6-page spread in the April/May Vogue Patterns magazine on “Adjusting for a Full Bust”. It is written by Kathryn Brenne (), and it has diagrams for adding darts, increasing darts, and princess seams. It also has measurements for determining starting cup size and increments for adjusting. You’d probably want the pivot-and-slide method for no-dart usage.

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