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Your bra size is built on two measurements. Start with the first step, measuring your underbust. Find your band size in 3 easy steps
How to determine your bra band in 3 steps
There are about 14 different band sizes available.
Although not every brand has the whole range of band sizes 28 – 54.
What's your bra size? See my calculator
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Step 1. Measure your bra band size
The smaller the band size you need, the smaller your underbust is.
For the band, measure directly under your breasts. Hold the measuring tape horizontally. Looking in a mirror will help.
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My advice is to measure a couple of times and write down the outcome.
It’s normal if you measure slightly different outcomes. By measuring a couple of times you can decide on the best measurement.
Measuring from your own home isn’t difficult. Ask someone to give you a hand if you like.
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Step 2. Check the feel of the band
It could be your measurements are in between two band sizes. You could round up to the nearest whole number.
- your band size should be firm but not too tight
- when you wear your bra for some time the band should still feel firm but comfortable
- do remember that the most support of your bra comes from the band
Step 3. Try different band sizes
Happy with the feel of the bra band? Does it feel supportive, but not too tight? That’s great.
Maybe you’re not sure and think you might need a smaller or wider bra band.
Going up or down a band size will automatically change the cup volume as well.
This happens when you go up a band size
You wear a bra 36C and want to go up a band size. You choose a band size 38. But when going up a band size the volume of the cups will change too. A 38C bra will have more cup volume than a bra in 36C.
If you want to keep the same cup volume you should try 38B.
This happens when you go down a band size
You wear a bra 36C and want to go down a band size. You choose a band size 34. But when going down a band size the cups will change too. A 34C bra will have less cup volume than a bra in 36C.
If you want to keep the same cup size you should try 34D.
Also, keep in mind that different brands may be sized a bit differently. If you know your bra sister size it will help you to know what sizes you wanna try.
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The average bra size UK
What's your bra size? See my calculator
Marks and Spencer Lingerie
Find the right bra at your M&S Store
M&S UK | M&S US | M&S CA | M&S AU