Why the tag is the next best thing to measuring
A bra she already wears is a fitting she has already done. She chose that size, tried it on and kept it. That makes the tag the most reliable source you can get without asking her. Only measuring together does better.
There is one condition. The bra has to fit her well. A tag on a bra she wears every week is strong evidence. A tag on a bra stuck at the back of the drawer may be telling you about a mistake. When the calculator asks whether the bra fits her well, an honest “not sure” drops the confidence from high to medium. That is the calculator being polite, not doubtful.
Step 1: choose the right bra
Pick a bra she wears often and seems comfortable in. Good signs:
- it is in regular rotation, not saved for occasions
- it looks worn in, without being worn out
- it is a structured bra with a band and cup size, not an S/M/L style
Avoid the newest bra if you do not know whether it worked out, and the oldest if the band has gone slack. If you can, check two or three everyday bras and see whether the sizes agree.
Step 2: find the label
The size is almost always on the back band, on the inside. Look near the hook-and-eye fastening, or along the side where the band meets the cup. Some bras have a printed stamp on the fabric instead of a sewn label. Others have a small label in the center panel at the front.
If there are several labels, one usually has the size and the others have care instructions and fabric. Take a quick photo rather than trying to remember it. Then put the bra back where it was. Folded the way it was, ideally. This is a surprise, not a forensic exercise.
Step 3: read the size
A bra size is a number followed by one or two letters, such as 34C or 32DD. The number is the band. The letters are the cup.
Many labels show the same size in several systems at once. A typical multi-country tag might list a US or UK size, an EU size and a French size side by side. For a US or UK 34C, it would read something like 34C, 75C and 90C, sometimes with AU 12C as well. They are not different sizes. They are the same bra described for different countries.
How to tell the systems apart:
- Bands in the 28–44 range are US or UK inches.
- Even bands from 6 to 22 are Australian or New Zealand sizes.
- Bands in steps of 5, such as 70, 75 or 80, are EU or French sizes. If two appear together, the higher one is French, because French bands are the EU band plus 15.
If the country is printed next to the size, even better. If it is not, the band number usually gives it away.
Step 4: enter it in the calculator
Choose “from her bra tag”, enter the band, the cup and the country, and answer whether the bra fits her well. The calculator gives the size in the system you choose, with its sister sizes and the equivalent in every other system.
This matters because cup letters change between countries above DD. A UK 34E is a US 34DDD. A US 36G is a UK 36F. If you read a UK tag and buy from a US shop without converting, you can end up a cup out. The bra size conversion page explains the pattern.
When the tag is cut off or faded
Labels get washed until they are blank, and plenty of people cut them out because they scratch. You have a few options:
- Check her other bras. Usually at least one still has a readable label.
- Look for a printed stamp on the inside of the band, which tends to outlast sewn labels.
- Look at packaging or receipts if she keeps them somewhere you share. Do not go looking in places you would not normally look, such as her email or accounts.
- Ask the shop she buys from. If she has a favourite lingerie shop, some keep a record of past purchases or fittings and can help with a gift, or suggest a gift card for the right range.
- Ask someone she would trust with it. A sister or a close friend may know her size, or can ask in passing. Only do this if she would be happy with that person knowing.
- Measure together. Not a surprise anymore, but a reliable result. See the measure together guide.
- Switch to a safe gift. A bralette in S, M or L, a robe or a gift card does not need a bra size at all.
When the sizes on her bras do not agree
It is normal for one person to wear more than one size. A 34D in one brand can be a 32DD or a 36C in another. Those three are sister sizes: about the same cup volume on a different band. Brands and styles also vary, so a plunge and a full-cup bra in her wardrobe may carry different labels.
If the sizes disagree, the most useful approach is:
- Buy from the same brand as her favorite bra, in the size on that bra.
- Or choose a style that is less sensitive to size, such as a soft bralette.
- Or choose a gift card, and include a note that tells her you made the effort.
What the tag will not tell you
The tag gives the size of that bra. It does not tell you how she feels about the style, how the shape suits her, or whether she would like another one. A size she wears in a t-shirt bra may not carry over to a plunge or a strapless bra.
So buy close to what she already wears. Same brand if possible, a similar style, and a color she actually chooses. Unlined, seamed bras are a safer pick than molded push-up cups if you are choosing the style yourself.
Practical checklist
- Read a bra she wears often and that fits well.
- Photograph the label, then put the bra back.
- Note the band, cup and country.
- Convert to the system of the shop.
- Buy in a similar style, with tags on and a gift receipt.
That is it. Five minutes of quiet detective work, and you will be choosing a gift with a size you can trust. If you would like more ideas for the gift itself, see the gift guide, or go back to the buying for her guide.
Sources & method: sizing rules follow the standard band-and-cup system used by UK, US, AU and EU brands, checked against fitting guides from specialist retailers and fitting communities. How we work.