Bust Cup Sizes

Bust Cup Sizes for Blocks, Patternmaking & Commerical Patterns are not to be confused with Bra Cup Sizes.  Your bra cup size will be similar, but maybe not the same.

How are Bust Cup Sizes Defined?

For the purposes of block and patternmaking, bust-cup sizes are based on the difference between the measurement of your Upper Bust and your Bust.  If you subtract your high bust from your full bust, the difference determines your cup size:


  • 1″ = A cup
  • 2″ = B cup
  • 3″ = C cup
  • 4″ = D cup
  • 5″ = DD cup (or E cup)
  • 6″ = DDD cup (or F cup)

Example Image

Note 1: The image below was updated on 11 April 2019.  My apologies but the image that was here previously was incorrect; the measurements were all over the place.  I must have had a brain freeze when I initally created and uploaded this as the measurements did not add up at all.  It wasn't until I went to reply to a comment I realised it was wrong.

In the image, the Upper Bust measurement is 34 inches.  The block for a B Bust cup (blue lines) will fit a bust of 36 inches - 2 inches more than the Upper Bust.  The block for a C Bust Cup (green lines) will fit a bust of 37 inches - 3 inches more than the Upper Bust. The block for a D Bust Cup (the pink lines) will fit a bust of 38 inches - 4 inches more than the Upper Bust.

Note 2: When I updated the image, I indicated the A cup line that would be used to create the block for a bust of 35 inches, but the A cup block isn't drawn (i.e. you can see the blue outline for the B cup, the green block outline for the B cup and the pink outline for the D cup, but there is no yellow outline for the A cup block).

bust-cups


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This comment was minimized by the moderator on the site

Hi. This is a great website. A lot of useful information, and very detailed. To much effort and dedication. I want to do a bodice block with your method, but I have a few doubts: my upper bust is 94 cms (37.79 '')., and my full bust is 98 cms....

Hi. This is a great website. A lot of useful information, and very detailed. To much effort and dedication. I want to do a bodice block with your method, but I have a few doubts: my upper bust is 94 cms (37.79 '')., and my full bust is 98 cms. (38.58 ''), there are difference between both are 1.58 inches. Which cup I have to choose: A cup or B cup ?

Thanks for any answer or suggestion. Greetings from Chile,
Sara.
Ps: Apologize for any writting mistake. I'm spanish spoken person.

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Hello Sara, so sorry it has taken me so long to answer, but I have just realised the Comment System has not been advising me when comments have been posted. Just found out that you left this comment a few minutes ago,,,

If the difference...

Hello Sara, so sorry it has taken me so long to answer, but I have just realised the Comment System has not been advising me when comments have been posted. Just found out that you left this comment a few minutes ago,,,

If the difference between your Upper Bust and Bust is 4cm, then you are pretty close to a B cup. If you look at the instructions for the Bodice Front, Figure 2, for a B-cup the line E is 1.25 inches (3.175cm) from the C-D line. However, as you are not quite a B cup, you could draw that line at about 2.5cm for a better fit. This will make the dart cup just that bit smaller and better fitting.

(Note: An A-cup extensión would be at 1.58cm from the C-D line).

Hope that makes sense. Let me know if it doesn’t. (Also hope you haven’t given up because I didn’t reply).

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Hello Sara,

I just realised that the measurements in this article originally were all over the place (i.e. incorrect!). For anyone trying to understand the concept it would have been very confusing. Just to let you know that I have corrected...

Hello Sara,

I just realised that the measurements in this article originally were all over the place (i.e. incorrect!). For anyone trying to understand the concept it would have been very confusing. Just to let you know that I have corrected the measurements in the text and in the image.

Regards
Maria

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This comment was minimized by the moderator on the site

Hello Maria. What should be done for someone with an A cup. What Would you suggest as an extention of the E line in inches, that is where there is a difference of 1inch from the bust to upper bust

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This comment was minimized by the moderator on the site

Hi there

A 1-inch difference is an A cup. For an A-cup go out 0.63 inch (1.5 cm) from the B~C line. (You could try between 0.63 and .087 inches). I have updated the Bodice Instructions to include this...
https://www.dresspatternmaking.com/blo...

Hi there

A 1-inch difference is an A cup. For an A-cup go out 0.63 inch (1.5 cm) from the B~C line. (You could try between 0.63 and .087 inches). I have updated the Bodice Instructions to include this...
https://www.dresspatternmaking.com/blocks/making-blocks/bodice-block/instructions-bodice-front-2dart

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Hello Maria. Thanks for all the information. Please what option is there for someone whose bust and upper bust is the same or where there is just one inch difference. by how many inches will the E line be extended. or will there be no extension...

Hello Maria. Thanks for all the information. Please what option is there for someone whose bust and upper bust is the same or where there is just one inch difference. by how many inches will the E line be extended. or will there be no extension at all

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This comment was minimized by the moderator on the site

Hello again

See the comment above.... A 1-inch difference is an A-cup - I have updated the instructions to include that.

In the case where there is absolutely no difference between the upper bust and the bust (a completely flat chest), then I...

Hello again

See the comment above.... A 1-inch difference is an A-cup - I have updated the instructions to include that.

In the case where there is absolutely no difference between the upper bust and the bust (a completely flat chest), then I imagine that you would just use the C~D line. In this case you wouldn't need a side seam dart - darts are for shaping around the bust, and if there is no bust, no shaping would be required. You would still need a waist dart to shape from the chest to the waist.

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Hello Charlie

I just realised that the measurements in this article originally were all over the place (i.e. incorrect!). For anyone trying to understand the concept it would have been very confusing. Just to let you know that I have corrected...

Hello Charlie

I just realised that the measurements in this article originally were all over the place (i.e. incorrect!). For anyone trying to understand the concept it would have been very confusing. Just to let you know that I have corrected the measurements in the text and in the image.

Regards
Maria

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This comment was minimized by the moderator on the site

Hello Maria,
Thanks a million for your response. i really appreciate. i just have one last question on this and i
promise not to bother again. i noticed an increase of about 0.63 inch between cup sizes. would you suggest i add 0.63 as i...

Hello Maria,
Thanks a million for your response. i really appreciate. i just have one last question on this and i
promise not to bother again. i noticed an increase of about 0.63 inch between cup sizes. would you suggest i add 0.63 as i increase cup sizes. for example a difference of 7 inches between upper bust and bust should i keep increasing by 0.63. thanks again

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This comment was minimized by the moderator on the site

Thanks soo much for your prompt response. My last question on this please. I noticed an increase of about 0.63 between each cup size. Do you suggest I keep adding 0. 63 as I go up in cup size. Like for some one with a difference of 7 inches...

Thanks soo much for your prompt response. My last question on this please. I noticed an increase of about 0.63 between each cup size. Do you suggest I keep adding 0. 63 as I go up in cup size. Like for some one with a difference of 7 inches between upper bust and lower bust, how many inche's will the distance of the E line. Thankss

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Hi, yes I would think so... Having said that, I've never made a block for anyone with a G or H cup, but the theory should hold.

Regards
Maria

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