Guides
Understanding cup sizes.
Cup letters only make sense next to a band number. This is the part of sizing that trips most people up.
A cup letter is relative, not absolute
A cup size isn't a fixed volume. It's the difference between your bust and your band. The same letter on a different band means a different actual cup. That's why a G can be modest on one person and large on another — the band it sits on is doing half the work.
32G and 36G are not the same
Because the cup is measured from the band, a 32G and a 36G have noticeably different cup volumes — the 36G is larger. The shared letter is misleading. When you compare bras or read reviews, the band and cup always travel together: think "32G", not "G".
Sister sizes
Sister sizes are sizes with roughly the same cup volume but a different band. Go down a band and up a cup, or up a band and down a cup, and the cup stays about the same while the band changes. For example, 32F, 30FF, and 34E are sisters — similar cup, different ribcage fit.
This is useful when a band feels too tight or too loose but the cup is right: a sister size keeps the cup and adjusts the band. Reviews often mention trying a sister size, which is worth watching for.
The D / DD / E / F / FF / G / GG ladder
UK sizing adds doubled letters as cups get larger, which is where confusion usually starts. After D comes DD, then E, then F, then FF, then G, then GG, and so on. They are sequential steps, not repeats — DD is one step above D, and FF is one step above F.
UK cup order, smaller to larger
Why The Cupsar uses UK sizing
The Cupsar uses UK sizing for your usual size so reviews can be compared consistently. Your usual size is the reference point people search by when they want reviews from users with similar fit patterns. The size worn in a specific review is different. That should be the size actually printed, selected, or sold for that bra. For example, someone whose usual size is 32G UK might review a US-market bra in 32DDD. Keeping those separate lets users compare by usual size without forcing everyone to do conversion math for every review.
Usual size and worn size
The Cupsar records two different sizes on a review, and they do different jobs.
Your usual size is your standardized UK reference size. It's what searching, filtering, and comparison run on, so it should always be entered with the UK band and cup dropdowns. Use it to find reviewers similar to you.
The worn size is the size you actually wore in the specific bra being reviewed — the size as that bra was labelled or sold. Read it to see what a reviewer actually tried in that particular bra.
You don't need to convert every bra into UK before submitting. Enter your standardized UK usual size once, then record the worn size exactly as the bra was labelled. For example, someone whose usual size is 32G UK might review a US-market bra worn in 32DDD — usual size stays 32G, worn size is 32DDD. That keeps the comparison data clean while still showing what was really worn.