October 13, 2020

How to Choose Your Cup Size

The joy of cup sized patterns like Cashmerette is that you can get an amazing fit straight away, without having to make tons of bust adjustments! But to do that it’s important to pick the right cup size, and today we’ll be showing you how.

how to choose your cup size

Cashmerette has a unique cup size system, with separate C/D, E/F and G/H cup size pieces on all our patterns. Because bra sizes are variable, we don’t recommend using your bra size to pick your size—instead, you’ll use your measurements. Here’s how!

Step 1: Take your measurements

Start by taking your high bust and full bust measurements.

To measure your high bust, place the measuring tape over the top of your bust and underneath your armpits. The tape will be horizontal at your back and front, and diagonal at your side. Keep your arms down when recording your high bust measurement (the model is lifting her arm so you can see where the tape goes). Take this measurement while NOT wearing a bra.

To measure your full bust, place the measuring tape around the fullest part of your bust. Keep your arms down when recording your full bust measurement.

Step 2: Circle your measurements on the body measurements chart

Here are the measurements charts for our two sizes ranges. You’ll want to find and circle your high bust and full bust measurements on the corresponding lines.

If your high bust is between sizes, always go up to the next size for your starting size.

Sizes 12-32

Sizes 0-16

Step 3. Consider three possibilities

1. Your high bust and full bust are in the same size.

Great! This means you can simply pick that cup size and carry on about your business.

For example, if your high bust is a 53″ and your full bust is a 57″, you would make the 28 E/F.

2. Your high bust is one size, and your full bust is in a larger size.

If your high bust is in one size, and your full bust is larger than any of the options in that size, you may need to do a full bust adjustment. Look at the largest cup option for that size, and subtract it from your full bust measurement to determine the size of your FBA.

For example, if your high bust is 53″ but your full bust is 59″, you’d start with a size 28 G/H (that has a full bust of 58″) and do a 1 inch FBA.

3. Your high bust is one size, and your full bust is in a smaller size

If your high bust is one size, and your full bust is smaller than any of the options in that size, you may need to do a small bust adjustment. Look at the smallest cup option for that size, and subtract your full bust measurement to determine the size of your SBA.

For example, if your high bust is 53″ but your full bust is 54″, you’d start with a size 28 C/D (that has a full bust of 56″) and do a 2 inch SBA.

And that’s how you choose your cup sizes in Cashmerette patterns! Let us know if you have any questions in the comments below.

22 thoughts on “How to Choose Your Cup Size

  1. Donna Greene says:

    I entered my measurements into the ‘find your size’ table and it said I need a SBA. But I have a small back so I am thinking what I really need is to take the back in. What should I do?

    1. Kelly says:

      Hey! If I were you, I’d start by getting a clearer idea of where measurements lie. Find something snug to wear that will give you a clear idea of where you side seams should be and take your measurements from seam to seam across the back at the shoulders, across the shoulder blades, across the lower back and across the back waist. Also measure your front in those same areas. This will allow you to get a clearer sense where you’re full and where you’re small. For example, I have a broad upper back, so though I measure in a 14 E/F in Cashmerette.sizing, I often do well with a C/D cup and a combination of brief shoulder and broad back adjustment. I also know that I have a long torso, even though I’m 5’7″, and that I I always need to add length.

      This Threads article does a good job of walking you through most measurements, though I would add those back and front seam to seam measurements, as well as a knee and upper thigh for future pants.


      I took a Craftsy class called Fast Track Fitting with Joi Mahon that explained how to compare these measurements to to your pattern to pre-adjust moist of your pattern. I find this saves me a lot of fabric by minimizing fitting adjustments.


      If all this seems too complicated, just get some cheap fabric and make up an experimental garment and see how well you like it (generally a good idea anyway). You’ll definitely be able to see how the back is lying and make your choices for your good garment.

  2. Penny Hollar says:

    I’m confused. Your instructions for determining cup size say to take the upper bust without a bra. Is the full bust measurement taken without a bra also?

    1. Ayelet says:

      Hi Penny, you should measure your full bust while wearing a bra (unless you don’t intend to wear a bra with the garment).

      -Ayelet at Cashmerette

  3. Erica says:

    What do I do if I have a very big difference in high busy vs full busy measurements?
    My high bust is 44″ and my full bust is 55″. How does sizing work then?

    1. The principles are exactly the same 🙂 But you’ll likely need to do Full Bust Adjustments on most patterns, even G/H on Cashmerette

  4. Donna says:

    Hi, I have Ahead of the Curve and have measured myself as HB46 FB50 WAIST50 CUPD UKSIZE26 Honeybourne. I have excess fabric above the bust as per the before photo of same, (page 52) I am hence trying to do an FBA. I don’t need to increase or decrease the horizontal fit, so I will reduce the side seams as per page55. The pattern is drafted for a C/D but the instructions are based on a C or D. I have cut the pattern as advised, do I use the C or D FBA ‘number’ to alter the pattern? Thanks 😊

    1. Ayelet says:

      Hi Donna, if you’re using the C/D cup size but need more room in the bust, you can avoid doing an FBA by trying the E/F or G/H cup size.

      -Ayelet at Cashmerette

  5. Friend has the following:
    Hip 44 Waist 39. High bust 47. Bust 45
    Says she wears a DD cup.
    Looks like she has a broad back.
    What size to sew or begin alterations?

  6. Mary Thomason says:

    My measurements came back 14 C/D. However, because I had a partial mastectomy so one side is a size D and the other is Size G cup. If I make a pattern with a non_woven material, i am afraid it will not be centered.

    1. Ayelet says:

      Hi Mary, you can try using an asymmetrical front, with the C/D cup size on one side and the G/H cup size on the other.

      -Ayelet at Cashmerette

  7. Cynthia says:

    Hello, My measurements (cm) are: high bust 106 (so round up to sz 18), and full bust 118. I think that would make me a sz 18 E/F bust. However, the size calculator put me at a 16G/H, but I’m a bit confused about how this would be so, as 16G/H has 117cm as its max. Many thanks for any suggestions 🙂

    1. Ayelet says:

      Hi Cynthia, I just responded to your email about this specific question, but in short, it depends on what bra cup size you tend to wear. Ultimately if you’re torn between two sizes, you can try one of those options on a muslin and see how you like the fit, and if it’s not working for you, you can switch to the other option.

      -Ayelet at Cashmerette

  8. Olivia leary says:

    I’m 5’ 1 3/4 inches tall your patterns are created for women 5’ 6”. How will height differences impact your patterns? How would I correct for the height difference?

    1. Ayelet says:

      Hi Olivia, it really depends on your proportions. We include lengthen/shorten lines on all of the major pattern pieces to help with this, so you can start there and see how your proportions match up to the design after making a muslin.

      We actually have a masterclass on length adjustments in the Cashmerette Club that goes over this in great detail. You can join at the Plus or All Access level to get access to the full library of masterclasses: cashmerette.com/club

      -Ayelet at Cashmerette

  9. sharon says:

    i bought the Rivermont pattern and im am having problems putting it together can someone help

    1. Ayelet says:

      We have a sewalong for the Rivermont here: https://blog.cashmerette.com/sewalongs/rivermont-dress-top-sewalong

      Also feel free to email us at hello@cashmerette.com for one-on-one support.

      Ayelet @ Cashmerette

  10. Robyn says:

    I’m very pear shaped, and I span between the two pattern types. Using your sizing calculator, I am 10 G/H bust, 14 waist, and 18 hip. What do you suggest I use? I often find tops are too wide and long in the shoulders and I only enough room for my hips with flared skirts. I also have a short torso.

    1. Ayelet says:

      Hi Robyn, I sent you an email directly but I would recommend trying the 0-16 size range first since it’s easier to grade up in the hips than grade down in the bust.

      -Ayelet at Cashmerette

  11. Kathleen says:

    Hello! I am full busted (36FF UK) and have the following measurements: High Bust: 39.8″, Full Bust: 43.5, Waist: 35.5 and Hip: 44.48. The Calculator is telling me to make the 16 C/D pattern, but just knowing about my bust I feel like this CANNOT be right and maybe I should try a 14 G/H? I just cannot understand how I could be a C/D and feel really silly that I can’t figure this out.

    1. Kathleen says:

      I’m a 36H in US bra sizes too, if that helps. So how can a C/D be the target – thanks!! I cannot make this make sense.

      1. Ayelet says:

        Hi Kathleen, the size calculator works on the difference between the high bust and the full bust, but that doesn’t always work for everyone! In your case, I would try the 14 G/H for the bust.

        -Ayelet at Cashmerette

Let me know what you think!