How to Measure Your Bra Size at Home
A straightforward guide to finding Your fit - no fitting room required.
(This post was originally published on May 20th 2018, updated on February 19th 2026)
Most of us were never taught how our bras should actually fit. We inherited sizes from shop assistants, guessed based on what felt 'close enough,' and quietly adjusted to discomfort we assumed was just part of wearing one. The digging underwire, the gaping cup, the band that rides up by midday - these aren't signs of a difficult body, they're signs of the wrong size.
The good news is that measuring yourself accurately takes less than five minutes, and the difference it makes to how you feel - in your clothes, in your posture, and in your skin is immediate and lasting. Yet, for most women, measuring has remained somewhat difficult, elusive - a tradition handed over to a stranger with a tape measure, repeated sporadically, and largely forgotten in between. It is time to reclaim it.
Knowing how to measure yourself accurately is not a technical skill reserved for professionals; it is a practical act of self-knowledge, and one worth making part of your regular routine. Your body changes and your size may shift and the woman who measures herself confidently every few months is the woman who knows exactly what she needs. This is not about chasing an ideal. it's about understanding your body well enough to dress it with intention.
Before You Begin
You’ll need a soft fabric measuring tape, a non-padded bra (something lightly lined rather than heavily structured), and a mirror if you have one to hand. Find a quiet moment - this works best done slowly, without rushing between other things.
The measurements below are taken in inches, which is the standard used in UK sizing. If your tape measure shows centimetres, a simple conversion online will take seconds.
Measuring Your Band Size
Begin by wrapping the tape measure snugly around your ribcage, directly underneath your bust. The tape should sit parallel to the floor and feel firm against your skin - not so tight that it digs in, but with no slack. Breathe naturally. The number you’re looking for is where the tape meets itself, measured in inches.
If that number is even, that is your band size. If it’s odd, round up to the next even number. So a measurement of 31 inches becomes a 32 band; 33 becomes a 34. This rounding ensures the band will sit with the right tension - supportive without constricting.
Measuring Your Bust
Next, measure around the fullest part of your bust - typically across the nipple line. Keep the tape level and relaxed; unlike the band measurement, this one doesn’t need to be pulled taut. Let it follow the natural contour of your body without compressing it.
Note this number down alongside your band measurement. These two figures are everything you need.
Calculating Your Cup Size
Subtract your band size from your bust measurement. The difference between those two numbers - in inches - determines your cup size. A difference of one inch is an A cup; two inches, a B; three inches, a C, and so on. The chart below maps out the full range across UK, EU and US sizing.
As a practical example: a bust measurement of 37 inches and a band measurement of 34 inches gives a difference of three inches - which corresponds to a C cup. Combined with the band, that’s a 34C.
Your complete bra size is simply your band measurement followed by your cup size.
Step 3. Calculate your cup size
To determine your bra cup size, simply subtract your band size from your bust measurement and refer to the bra cup size chart.
For Example:
Bust measurement: 37 inches
Band measurement: 34 inches
Subtracting 34 from 37 gives us 3 inches
3 inches according to the bra size chart, the Cup measurement is C Cup.
Taking a look at our bra size chart, you will see that a difference of 3 inches corresponds to a C cup.
Now, combine this cup size with your band measurement of 34 inches, and there you have it!
Your perfect fit is a 34C bra.
A Note on Fit Across Brands
Once you have your measurements, it’s worth knowing that sizing isn’t perfectly consistent across every brand or style. A 34C in one label may feel slightly different from the same size in another, because cut, fabric, and construction all influence how a bra ultimately fits on the body. Consider your measurements a reliable starting point rather than a fixed answer - one that gives you the confidence to try things on with knowledge rather than guesswork.
If you find yourself between sizes, or if a particular style doesn’t sit quite right despite being your size, that’s normal. Bra fitting is a conversation between your measurements and your shape, and sometimes it takes trying two or three variations to find the one that feels right for both.
How Often Should You Remeasure?
Bodies change - gradually, seasonally, and sometimes without us noticing. Weight fluctuation, hormonal shifts, pregnancy, and the natural changes that come with age all affect how a bra fits. Remeasuring every six months is a reasonable rhythm for most women, though any significant physical change is a good reason to check your measurements sooner.
Treating your bra size as something fixed - something decided once and carried forward indefinitely - is one of the most common reasons women end up in the wrong size without realising it.
If you’d like to go further, our Bra Size Calculator in the Fitting Room will cross-reference your measurements instantly. And for those who want a more detailed guide to take into a fitting appointment - including visuals and notes on specific bra styles - our How to Measure Your Bra Size ebook is available in the shop.
There is something quietly powerful about knowing your own measurements. Not because a number defines you, but because it removes the uncertainty that so many women carry into a lingerie purchase - the second-guessing, the compromising, the settling for ‘near enough.’ You deserve a bra that fits the body you have today, and the knowledge to find one.
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