Calculate Your UK Bra Size

Enter your measurements in inches for accurate UK sizing. Measure wearing a non-padded bra or no bra.

Measure firmly around ribcage, just below breasts
Measure at the fullest part of your bust

International Size Converter

Convert between UK, US, and EU bra sizes.

Find Your Sister Sizes

Sister sizes have the same cup volume but different band sizes. Useful when your usual size isn't available or for finding a better fit.

Bra Fit Check

Check if your current bra fits correctly. A well-fitting bra should feel comfortable and supportive.

How to Measure Your Bra Size

1

Get Ready

Wear a non-padded bra or go braless. Use a soft measuring tape. Stand straight with arms relaxed at your sides.

2

Measure Underbust

Wrap the tape firmly around your ribcage, just below your breasts. Keep the tape level and snug (not tight). This is your band measurement.

3

Measure Bust

Wrap the tape around the fullest part of your bust (usually at nipple level). Keep the tape level but not tight. This is your bust measurement.

4

Calculate

The difference between bust and underbust determines your cup size. Each inch of difference equals one cup size (1" = A, 2" = B, etc.).

UK Cup Size Chart

Difference (inches) UK Cup Size US Cup Size
0-1"AAAA
1"AA
2"BB
3"CC
4"DD
5"DDDD/E
6"EDDD/F
7"FDDDD/G
8"FFH
9"GI
10"GGJ
11"HK

UK Band Size Chart

Underbust (inches) UK Band Size EU Band Size
26-27"2860
28-29"3065
30-31"3270
32-33"3475
34-35"3680
36-37"3885
38-39"4090
40-41"4295
42-43"44100

Common Bra Fit Issues & Solutions

Band Rides Up

The back band lifts up instead of staying level.

Solution: Try a smaller band size or tighten the band.

Straps Dig In

Shoulder straps leave marks or cause pain.

Solution: Try a smaller band (straps shouldn't carry the weight) or wider straps.

Spillage Over Cups

Breast tissue spills over the top or sides of the cup.

Solution: Try a larger cup size or fuller coverage style.

Gaps in Cups

Cups wrinkle or gap at the top or sides.

Solution: Try a smaller cup size or different cup shape.

Underwire Poking

Underwire sits on breast tissue or pokes ribs.

Solution: Try a different cup size or wire-free style.

↔ Centre Gore Lifts

The centre piece doesn't sit flat against chest.

Solution: Try a larger cup size or plunge style.

Frequently Asked Questions

How do I measure my bra size at home?

Wear a non-padded bra or no bra. Measure your underbust firmly around your ribcage just below your breasts (this is your band size). Then measure your bust at the fullest part. The difference in inches determines your cup size: 1" = A, 2" = B, 3" = C, and so on. Use a soft measuring tape and keep it level.

What are sister sizes and how do they work?

Sister sizes are bra sizes with the same cup volume but different band sizes. For example, 34C, 32D, and 36B are all sister sizes with equivalent cup volume. If your band feels too tight, try your sister size up (e.g., 32D instead of 34C). If too loose, try the sister size down (e.g., 36B instead of 34C).

How does UK bra sizing differ from US sizing?

UK and US band sizes are the same (28, 30, 32, etc.). The difference is in cup progression after D. UK uses: D, DD, E, F, FF, G, GG, H. US uses: D, DD/E, DDD/F, DDDD/G, H, I, J, K. So a UK 34F is approximately a US 34G. Always check the brand's origin for accurate sizing.

How often should I remeasure my bra size?

Experts recommend remeasuring every 6-12 months, or after significant weight changes, pregnancy, breastfeeding, or hormonal changes. Studies show about 80% of women wear the wrong bra size, often because they haven't been fitted recently.

Why does my bra size vary between brands?

Just like clothing, bra sizing isn't completely standardised. Different brands use different patterns, materials, and size scales. European brands may run smaller, while some high street brands run larger. Always try before buying, and don't be surprised if you need different sizes in different brands.

How do I know if my band size is correct?

A correct band should be snug but comfortable on the loosest hook (leaving room to tighten as the bra stretches over time). You should be able to fit two fingers under the band. It should sit level and parallel to the floor, not ride up at the back. The band provides 80% of support.

What if I'm between sizes?

If you're between sizes, try both options and their sister sizes. Cup shape matters too - some styles suit certain breast shapes better. Consider the style (full cup, balconette, plunge) as this affects fit. Many experts recommend sizing down in the band and up in the cup if between sizes.

How do I convert my UK size to EU?

For EU band sizes: add 18 to the UK band number and multiply by 2.5. So UK 32 = EU 70, UK 34 = EU 75, UK 36 = EU 80. EU cup sizes use numbers instead of letters, but many EU brands now use UK/US letters. French sizing is the same as EU for bands but uses different cup notation.

UC

Reviewed by: UK Calculator, Founder & Developer

Founder & Developer - UKCalculator.com

The UK Calculator team is the founder and developer of UKCalculator.com, providing free, accurate calculators for UK residents.

Important Note

This calculator provides estimates based on standard UK sizing formulas. Individual fit varies based on body shape, breast tissue distribution, and bra style. For the best results, try on multiple sizes and styles. Professional fitting services are available at most lingerie retailers in the UK.