Bra fitting guides

Practical, body-neutral guides to UK bra sizing, from taking your measurements to checking the fit in the fitting room.

These guides explain how UK bra sizes work, how to measure accurately, and how to tell whether a bra fits. They also cover what to do when a measured size does not feel right, how breast shape and bra style affect fit, and how sizing changes through pregnancy, after surgery and when choosing a first bra. Each guide links to the sizing tools it explains, so you can move from reading to checking your own size.

Measuring

How to measure

The four measurements, step by step, with diagrams.

Common measuring mistakes

The errors that most often give the wrong size.

Accuracy and limitations

What a calculator can and cannot tell you.

Understanding sizes

How UK bra sizes work

What the number and the letters mean.

Sister sizes explained

Why 34C, 32D and 36B share a cup volume.

UK bra size chart

Every UK band and cup in inches and centimetres.

Getting the fit right

How to tell if your bra fits

A step-by-step fit check for the fitting room.

Bra fit problems

What causes each fit problem, and the fix.

Why your size feels wrong

Brand, shape, style and method differences.

Breast shapes and bra styles

How shape affects which styles fit.

Life stages and specialist fitting

Pregnancy bra size changes

When to re-measure and what to buy.

Post-mastectomy bra fitting

Pockets, band comfort and specialist fitting after surgery.

First bra guide for parents

For parents and carers supporting a first bra.

Bra styles

Bra styles

How each bra style is built and who it suits.

Sizing tools

Sister Size Calculator

Every size with the same cup volume, and when to try each.

Bra Size Converter

UK, US, EU, FR, and AU sizes side by side.
.

Cup Volume Comparison

See which of two bra sizes holds more, and understand why.

Fit Diagnosis

Select your fit problems and get a specific size to try.

No Tape Measure

Get a rough bra size estimate from a bra you already own or your dress size.

Nursing Bra Calculator

Find your bra size through pregnancy and breastfeeding.

Sports Bra Calculator

Find the right size and support type for your activity.

Plus Size Bra Calculator

Find the right size for larger bands and fuller cups.

Strapless Bra Size

Find the firmer band size a strapless bra needs for a secure fit.

Size Tracker

Track bra size changes over time, with your data stored only on your device.

Bra size calculator

Four measurements, both band methods, sister sizes and a confidence score.

Sophie Dixon

Sophie Dixon

Hi, I’m Sophie Dixon, the creator of UK Bra Size Calculator. I built this tool because I was tired of seeing women guess their bra size from outdated charts that rarely fit right. I researched UK bra fitting standards and measurement methods in depth so I could offer both the modern and traditional sizing approaches side by side – giving you an honest comparison instead of a single guess. Everything runs privately in your browser, and I’m always refining the calculator to make it more accurate.