Up to 80% of women wear the wrong bra size. Our fitting guide and calculator use the same method as our in-store experts to help you discover the right fit — from home.
What you’ll need
Your current best-fitting bra, ideally less than a year old
A tape measure
A large mirror to check that your bra fits correctly
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Step 1 of 3
Take Your Measurements
Wear an unpadded bra and stand with relaxed arms and shoulders. You’ll take two measurements — your under-bust and your over-bust.
Under-bust: place the tape around your body directly underneath the bust, holding it straight and tight around the body. Take the measurement immediately after exhaling.
Over-bust: keeping the tape in the same position on your back, move it up loosely over the fullest part of the bust, holding it horizontally.
Measure in inches
Measure at the fullest point
Triumph Tip
The tape measure is not elastic but the bra is — so it’s essential the tape is held firmly around the body when you measure.
Private by design — your measurements are calculated in your browser and are never saved to your account or stored on our servers, even when you’re signed in. See our Privacy Policy.
Your result is a recommended starting size. Fit varies by style, fabric, and body shape, so use it as a guide — explore our fit tips or visit a store for a professional fitting.
The Perfect Fit
How your bra should look — and how to tell when it’s time to re-measure. Guidance from Triumph’s fitting experts.
How your bra should look
The band sits level all the way around your back, the side seam and underwire rest at your underarm, and the centre lies flat against your chest — with the cups containing you fully, no spillage and no gaping.
Check Your Fit
If you notice any of these, it’s time to re-measure and find your true size.
If Your Bra Is Riding Up
Check the back of your bra. If it rides up, the bra is too big around the body. Try a smaller size.
If the Cup Feels Uncomfortable
The side seam or underwire should sit at the underarm. If it sits too far forward into bust tissue, the cup is too small — try a larger cup. If it sits too far back into the armpit, try a smaller cup.
If Your Bra Doesn’t Sit Flat
If the bra sits out at the centre front and doesn’t sit flat against the chest, the cup size is too small. Try a larger cup size.
We recommend re-measuring every 6 to 12 months, or whenever you notice changes in how your bra fits. Weight fluctuations, hormonal changes, pregnancy, and aging can all affect your size. If you notice straps slipping, band riding up, or cups not fitting as they used to, it's time to re-measure.
Sister sizes are bra sizes that share the same cup volume but with different band sizes. For example, 34C, 36B, and 32D are all sister sizes with the same cup volume. If a bra fits well in the cups but the band is too tight or loose, trying a sister size can give you a better fit without changing the cup volume.
If your underbust measurement falls between two even numbers (e.g., 33 inches), you have options. If you prefer a snugger fit, round down to 32. If you prefer more comfort, round up to 34. Remember that different bra styles and materials also affect how a band feels — stretchy fabrics tend to run looser.
Band sizes are the same (32, 34, 36...) but cup labels differ above a D cup. Triumph product cup labels run D, DD, F, G, H. If you've seen DDD or E elsewhere, that's the same cup as our F. If you know your UK size, our size chart can help you convert.
For the most accurate results, measure without a bra or in a thin, non-padded bralette. Padding adds extra volume to your bust measurement, which can lead to an incorrect cup size recommendation. Stand naturally and don't hold your breath while measuring.
It depends on your needs! Minimizer bras are ideal for fuller busts who want a streamlined silhouette. T-shirt bras give a smooth, invisible look under clothes. Push-up bras enhance and lift. Wireless bras prioritize comfort and freedom. Use Step 3 of our calculator to tell us what you're looking for, and we'll recommend the perfect style from our collection.
