UK Bra Size Visual Comparison Tool

How to Use the UK Bra Size Visual Comparison Tool

Select a UK band size and cup size for both Size 1 and Size 2 to compare any two of the 220 UK bra sizes currently manufactured for the UK market. The tool instantly updates with original bra size illustrations, estimated underbust and fullest bust measurements, and explains whether the two sizes are sister sizes.

You can compare neighbouring cup sizes, sister sizes or completely different bra sizes to better understand how cup volume, band size and overall bra size relationships change across the modern UK sizing system.

Try the example first
Explore the 34F vs 38DD comparison below to see how sister sizing works, then choose any two of the 220 UK bra sizes to compare instantly.

Compare Two Bra Sizes

Important:

These illustrations are simplified visual guides. Real bra fit depends on measurements, breast shape, style, fabric, wire width and brand sizing. Use this tool to understand size relationships, not as an exact prediction of how a bra will fit.

Bra Size Calculator
Bra Size Converter
Bra Sister Sizes Explained
UK Bra Cup Size Chart
Bra Fitting Advice

Looking for more background on how bra sizing developed? The Wikipedia guide to bra sizing provides a general overview of bra size systems and their history. This page focuses specifically on visual comparisons using the modern UK bra size sequence.

Can I compare any UK bra sizes?
Yes. This tool compares all 220 UK bra sizes currently manufactured for the UK market. Select any two sizes to compare their band size, cup volume, estimated fullest bust measurement and sister size relationship.

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What bra sizing system does this comparison tool use?
The calculator is based on the modern extended UK cup sequence: AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, L and LL. This allows accurate comparison across the full UK manufactured size range.

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Are sister sizes exactly the same?
No. Sister sizes have approximately the same cup volume but different band lengths. They are often used when changing band size while maintaining a similar cup volume.

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Why do the cup letters sometimes decrease as the band size increases?
Cup letters represent cup volume relative to the band size. As the band size increases, the cup letter decreases to maintain approximately the same cup volume. This is why sizes such as 34F and 36E are sister sizes.

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Can I compare US or EU bra sizes?
This version compares UK bra sizes. Dedicated US, EU and AU versions of the Visual Comparison Tool are planned for future release.

Remember

This comparison tool helps you understand how UK bra sizes relate to one another, but every bra style and every body shape is different. Use your measurements together with our Bra Size Calculator and Bra Fitting Advice to achieve the best possible fit.