How to Measure Your Bra Size at Home: An Easy Guide

Most of us are wearing the wrong bra size without realising it—and it makes all the difference to comfort, support and how your clothes sit. The good news? You can measure yourself accurately at home in just a few minutes using nothing more than a soft measuring tape.

Whether you're shopping for an everyday bra, a wireless style or something for a special occasion, this simple guide will help you find your best fit.

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What You'll Need

Before you begin, gather:

• A soft measuring tape

• A mirror

• A non-padded bra (or no bra)

• A few minutes in front of the mirror

For the most accurate results, measure over bare skin or a thin, non-padded bra. Avoid measuring over thick clothing or heavily padded bras, as they can affect your measurements.

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Step 1: Measure Your Band Size

Your band size forms the foundation of your bra fit and provides most of the support.

How to measure

1. Stand upright with your shoulders relaxed.

2. Wrap the measuring tape around your ribcage, directly underneath your bust.

3. Keep the tape snug and level all the way around.

4. Breathe out naturally and note the measurement in centimetres.

This is your underbust measurement, which determines your UK band size (the 32, 34, 36 part of your bra size).

Expert tip: A new bra should fit comfortably on the loosest hook. As the elastic naturally relaxes over time, you'll be able to fasten it on the tighter hooks, helping extend its lifespan.

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Step 2: Measure Your Bust

Next, measure around the fullest part of your bust.

How to measure

1. Wrap the tape around the fullest part of your bust.

2. Keep it level all the way around.

3. Let the tape rest gently against your body without pulling it tight.

4. Record your measurement.

This is your overbust measurement.

The difference between your bust and underbust measurements helps determine your cup size.

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Bra Size Difference Guide

Use the table below as a helpful starting point.

Difference Between Bust & Underbust	Approximate Cup Size
10–11 cm	AA
12–13 cm	A
14–15 cm	B
16–17 cm	C
18–19 cm	D
20–21 cm	DD / E
22–23 cm	F
24–25 cm	FF
26–27 cm	G

Sizing can vary slightly between brands, so always refer to the size guide on the product page.

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UK Band Size Guide

Underbust Measurement	UK Band Size
68–72 cm	32
73–77 cm	34
78–82 cm	36
83–87 cm	38
88–92 cm	40
93–97 cm	42

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Five Signs Your Bra Doesn't Fit Properly

Even if the label says it's your usual size, your bra may not be giving you the support you need.

The band rides up at the back

A band that lifts away from your body is usually too loose. Since the band provides most of the support, try a smaller band size or a sister size.

The cups gape or wrinkle

If there's empty space in the cups, they may be too large or the bra shape may not suit your bust.

Breast tissue spills over the cups

If you're spilling over the top or sides, the cups are likely too small. Going up a cup size can often solve the problem.

Your straps dig in or constantly slip

Straps should provide stability, not carry all the weight. If they're doing all the work, the band probably isn't supportive enough.

The centre of the bra doesn't sit flat

The centre panel (known as the gore) should rest comfortably against your chest in most underwired bras. If it doesn't, you may need a larger cup size.

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Between Sizes? Try Sister Sizes

If one bra feels almost perfect but not quite, sister sizing may help.

For example:

• 34C has a similar cup volume to 32D and 36B.

• 36D is similar to 34DD and 38C.

If the cups fit but the band feels too tight, try going up a band size and down a cup. If the band feels too loose, do the opposite.

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Common Measuring Mistakes

Avoid these common mistakes for the most accurate result:

• Measuring over a padded bra

• Pulling the tape too tightly

• Holding your breath

• Letting the tape slope at the back

• Measuring around your waist instead of directly beneath your bust

• Assuming every brand fits exactly the same

• Not remeasuring after weight changes or pregnancy

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Frequently Asked Questions

How often should I measure my bra size?

Every six to twelve months, or sooner if your weight, hormones or body shape change.

Do bra sizes vary between brands?

Yes. Different brands use different patterns and fabrics, so your best fit may vary slightly.

Can my bra size change?

Absolutely. Weight changes, pregnancy, breastfeeding, menopause and regular exercise can all affect your bra size.

Should the straps carry most of the support?

No. Around 80–90% of your bra's support should come from the band.

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Finding the Right Style

Once you've found your size, choosing the right style becomes much easier.

• Wireless Soft Bras are perfect for all-day comfort and gentle support.

• Soft Bras offer a natural shape with flexibility and comfort.

• Padded Bras provide additional shaping and a smooth silhouette beneath clothing.

• Full Cup Bras are ideal for maximum coverage and support.

• Balconette Bras create a flattering neckline and work beautifully under wider necklines.

Choosing a style that suits both your body and your lifestyle is just as important as choosing the right size.

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Final Thoughts

Finding your bra size doesn't have to be complicated. With just a measuring tape and a few minutes at home, you can discover a size that offers better comfort, support and confidence.

Your measurements are the perfect place to start, but remember that every brand fits slightly differently. The most important thing is how your bra feels when you wear it.

At Spanties, we carefully curate premium European lingerie designed to combine comfort, quality and timeless style. Whether you're looking for an everyday favourite, a supportive wireless bra or an elegant padded style, we're here to help you find your perfect fit.

Browse our bras collection to find your perfect fit, discover matching pieces in our Love & Lace lingerie edit, or complete the look with our hosiery and tights collection. Prefer a personal recommendation? Get in touch with our Dublin team for tailored sizing advice.