Bra Size Calculator

Bra Size Calculator FAQ

How do I calculate bra size from measurements?

Measure around your ribcage under the bust and around the fullest part of the bust, then work out the difference. This calculator takes six readings: three underbust (Loose underbust, Snug underbust, Tight underbust) and three bust (Standing bust, Leaning bust, Lying bust). Your band is the Snug underbust rounded to the nearest even number, the bust is the average of the three bust readings, and each inch of difference between the two is one cup size.

What are the six measurements in a 6 measurement bra size calculator?

Three around the ribcage directly under the bust, taken with the tape resting on the skin (loose), firm but comfortable (snug) and pulled as tight as you can hold (tight). Three around the fullest part of the bust, taken standing upright, leaning forward with your torso about parallel to the floor, and lying flat on your back.

How do I measure my underbust for a bra?

Wrap the tape around your ribcage directly under the bust, level all the way round, in a soft unpadded bra or none. Take it three times: resting on the skin with no pressure, firm but comfortable, then pulled as tight as you can hold. Enter them under Loose underbust, Snug underbust and Tight underbust. Each reading must be the same as or smaller than the one before.

How do I measure bra size at home with a tape measure?

All you need is a soft tape measure and a mirror. Take the three underbust readings, then the three bust readings at the fullest part of the bust with the tape level at the back: standing, leaning forward, and lying on your back. Type all six in, choose Centimeters or Inches, and select Calculate size.

Can I use centimeters instead of inches?

Yes. Choose Centimeters or Inches under Units. The calculator starts from the unit that is usual in your region, and switching converts the numbers you have already typed. If a measurement looks unusual for the unit you chose, it shows a hint to check the unit.

How do I convert a UK bra size to a US size?

The band number is the same in both systems. Only the cup letters differ after the first four: UK goes A, B, C, D, DD, E, F, FF, G, GG, H, while US goes A, B, C, D, DD/E, DDD/F, G, H, I, J, K. The calculator shows both from the same measurements, in the UK size and US size cards.

What is 34FF in US size?

On this chart, UK 34FF is 34H in the US. FF is the eighth cup (a difference of 8 inches), and the eighth US cup is H. Use the cup table above to look up any other letter.

What are sister sizes?

Sister sizes fit a similar volume with a different band: go up a band and down a cup, or down a band and up a cup. For a 34D, that gives 36C and 32DD. After you calculate, try a sister size if your first fit feels too loose or too tight in the band, or the cups are too big or too small.

Is a bra size calculator accurate?

It gives a starting size, not a fitting. Bands and cups vary by brand and style, and a calculator cannot see how a bra sits on you. Treat the result as the size to try first, and use sister sizes to adjust. For a hard-to-fit shape, a professional fitter can help.

Why does it say Smaller than cup A on this chart?

Your average bust is less than one inch more than your band, so the chart has no cup for it. Re-check the bust readings, especially that the tape was level at the back. The message Larger than this chart covers means the average bust is more than 11 inches over the band, past UK H and US K.

Does the calculator add 4 inches to the underbust?

No. Your band comes from your Snug underbust rounded to the nearest even number, for example 33 becomes 34. The older rule of adding inches to the underbust is not used. Loose underbust and Tight underbust only check that your readings are in a believable order and do not change the size.