UK Bra Size Calculator | Bra Size Calculator UK

Bra size calculator

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Quick answer

How do you calculate a UK bra size?

To use a UK bra size calculator, measure snugly around the ribcage for the band, measure around the fullest part of the bust, then compare the difference using UK cup progression. The result is an estimate to start fitting from, not a guarantee that every UK brand will fit the same.

Unit

Use inches for the simplest UK band estimate, or centimetres if that is how you measured.

Band

The band should be firm and level because most support comes from the band, not the straps.

Cup

UK cups usually progress D, DD, E, F, FF, G, GG, H, so do not assume US cup labels match after D.

How UK Bra Sizing Works

A bra size calculator UK shoppers can use should start with two measurements: underbust for the band and bust for the cup difference. UK bra sizing combines an inch-based band number with a cup letter based on the difference between your bust and underbust. A result like 32F means the band is in the 32 range and the cup volume follows the UK cup progression for that band.

Measure your band

Wrap the tape around your ribcage directly under the bust. Keep it level, snug, and close to the body without pulling so hard that it distorts your breathing.

Measure your bust

Measure around the fullest part of the bust while keeping the tape level across your back. A soft, non-padded bra can help if it keeps tissue supported without compressing it.

Compare the difference

The cup letter is estimated from the difference between bust and band measurements. UK sizing keeps band and cup connected, so a 32F and 34E do not fit the same around the body even though their cup volumes are sister sizes.

Detailed measuring guideReview underbust and bust tape placement before calculating.

UK Bra Size Measurement Infographic

Save or open this UK measurement infographic when you want a visual reminder of where to place the tape before using the calculator. It shows underbust measurement, bust measurement, cup difference, and a simple UK size example.

Full measuring guideRead detailed tape-placement guidance before calculating.

UK Cup Progression After D

The UK cup sequence is one of the most important differences to understand. Many UK brands use double letters at several points, so a UK F, FF, or G should be compared by system rather than by letter alone.

Common UK cup progression compared with approximate US labels
Cup step	Common UK label	Common US label
4	D	D
5	DD	DD/E
6	E	DDD/F
7	F	G
8	FF	H
9	G	I
10	GG	J
11	H	K

UK bra size chartSee UK band and cup labels in chart form.Bra sizing by countryCompare UK labels with other regional systems.

UK Bra Size Conversion

Use conversion as a label guide when shopping international brands. Band labels often convert predictably, but cup labels can diverge once you move past D. Always check whether the retailer uses UK or US cups before ordering.

Common UK bra size label equivalents
UK example	US	EU	France	AU/NZ	Japan	Italy
32C	32C	70C	85C	10C	70C	2C
34D	34D	75D	90D	12D	75D	3D
36DD	36DD/E	80E	95E	14DD	80E	4E
32F	32G	70G	85G	10F	70G	2G

UK to US converterConvert UK labels into closest US equivalents.

UK bra size chart used as a visual reference for conversion — Conversion is a shopping guide, not a fit promise.View full size

Worked UK Bra Size Examples

Examples help show how measurements become a starting label. Use them as a sanity check, then confirm the result with the calculator and fit signs.

31 inch underbust + 37 inch bust

A 31 inch underbust typically starts near a 32 band. A 6 inch bust difference points around a UK E/F range depending on rounding and brand fit, so the calculator gives a starting size to try rather than a final verdict.

34 inch underbust + 39 inch bust

A 34 inch band with about 5 inches of difference often starts near UK 34DD. If the cups spill, move up in cup; if the band rides up, compare a firmer sister size.

32F feels tight in the band

Try the sister size 34E if cup volume feels close but the band is too firm. If the cup also feels small, change cup volume instead of only changing the band.

UK Shopping Notes Before You Buy

When shopping from a UK retailer, confirm whether the brand is using UK cup progression. When shopping an international brand from a UK site, check the size chart because a product page can display UK bands while still using a brand-specific cup sequence.

Check the brand's size system

Do not assume an E, F, or G cup means the same thing across UK and US brands. Look for a brand chart, conversion note, or country selector.

Use fit symptoms to refine

Gaping, spilling, a floating centre gore, or a band riding up are more useful than the label alone.

Common UK Bra Sizing Mistakes

Most UK sizing problems come from mixing systems or treating the label as more precise than it really is. Start with measurements, then use fit symptoms to refine.

Confusing UK and US cup sizes

A UK DD often looks familiar to US shoppers, but the sequence after D can split quickly. Check whether the brand is using UK or US cups before assuming an E, F, or G means the same volume.

Choosing a loose band

The band should feel firm and level because it does most of the support work. If the back rides up, the band may be too loose even if the cups seem comfortable at first.

Assuming every UK brand fits the same

Two UK bras with the same label can still differ in cup depth, wire width, gore height, and fabric stretch. Treat the calculator result as a starting size, not a guarantee.

Fit Tips for UK Bra Sizes

The band should sit level on the loosest comfortable hook when the bra is new. Cups should hold tissue without gaping or spilling, the centre gore should sit close to the sternum when the style allows it, and straps should fine-tune lift instead of carrying the whole weight.

Common fit problemsDecode gaping, spillage, slipping bands, and strap issues.

UK Sister Sizes

Sister sizes keep similar cup volume while changing band tension. If 32C feels tight in the band, try 34B. If 32C feels loose, try 30D. For larger UK cups, the same rule applies: 32F, 34E, and 30FF are nearby volume relatives with different bands.

Sister size calculatorAdjust band size while keeping cup volume close.Understanding sister sizesLearn why band and cup changes move together.

Why Your UK Bra Size May Vary by Brand

UK sizing gives you a shared language, but brands still draft bras differently. A plunge, balconette, full cup, and sports bra can all feel different in the same size because the pattern, wire shape, fabric recovery, and cup height are doing different jobs.

Expert review

Reviewed by Sarah Williams

This UK calculator guide is reviewed for measurement clarity, UK cup progression, conversion guidance, and practical fit language so the page helps shoppers make a better first size choice.

Role: Certified bra fit specialist
Credential: Professional bra fitting and specialty-fit review
Last reviewed: May 2026
Next review: August 2026

About our review process

Methodology

How this UK calculator guide is built

The calculator estimates a starting size from underbust and bust measurements, then the guide explains how that result should be checked against real fit signs. It is fit guidance for bra shopping and does not replace personal fitting advice for pain, injury, surgery recovery, or medical concerns.

The calculator keeps measurement entry separate from brand claims so results do not depend on one retailer.
UK cup guidance highlights the DD/E/F/FF/G sequence because that is where many US and UK comparisons break down.
Conversion tables are label equivalents for shopping; brand charts and try-on fit still matter.
Editorial review focuses on clarity, country-specific usefulness, and avoiding unsupported medical claims.

Editorial standardsRead how calculator content and fit guidance are reviewed.How to measureCheck tape placement before relying on any calculated size.

United Kingdom Bra Size FAQs

Is UK bra sizing the same as US bra sizing?

Not exactly. UK and US bands often look the same, but cup progression can differ after D. A UK F, for example, may not match the label a US brand uses for the closest cup volume.

How do I calculate my UK bra size?

Measure snugly under the bust for the band and around the fullest part of the bust for cup volume. Enter both measurements in the calculator above, then use the result as a starting point for fit checks.

What is the UK cup progression after D?

Many UK brands use D, DD, E, F, FF, G, GG, H, HH, J, and onward. This is why a UK F may not match the same letter in a US brand.

Why does my UK bra size feel different between brands?

Brands can use different cup shapes, wire widths, fabric stretch, and style patterns. The same UK size can feel different in a plunge bra, full-cup bra, balconette, or sports bra.

Should I measure in inches or centimetres for a UK bra size?

Inches are usually the simplest starting point for UK band labels, but centimetres can still be entered if that is how you measured. The calculator can accept either unit.

Keep Comparing Sizes

How to measure bra size in the UK