Calculate Your Bra Size Online - US UK and EU Sizing

How to Find Your Bra Size

Finding the correct bra size is essential for comfort and support. This bra size calculator helps you determine your size using two simple measurements. You can use inches or centimeters and get your size in US, UK, and EU sizing standards all at once.

A well-fitting bra should feel comfortable and supportive without digging into your shoulders or riding up your back. Many people wear the wrong bra size without realizing it. Using this calculator is the first step toward finding your perfect fit.

How to Measure for Bra Size

To get accurate measurements you will need a soft measuring tape. Take measurements while braless or wearing a non-padded bra for best results.

Underbust measurement: Measure around your ribcage directly under your bust. The tape should be snug but not tight. Make sure it is level all the way around.
Bust measurement: Measure around the fullest part of your bust. Keep the tape loose enough to breathe comfortably. Note this measurement down.

Enter these two measurements into the calculator and your bra size will be displayed instantly in US, UK, and EU sizing systems.

How Bra Size Is Calculated

The bra size consists of a number (band size) and a letter (cup size). The band size is derived from the underbust measurement rounded to the nearest even number in inches. In EU sizing the band is measured in centimeters and rounded to the nearest multiple of 5.

The cup size is determined by the difference between the bust and underbust measurements. Each inch of difference corresponds to a cup size:

Less than 1 inch: AA cup
1 inch: A cup
2 inches: B cup
3 inches: C cup
4 inches: D cup
5 inches: DD cup (US) / DD cup (UK)
6 inches: DDD cup (US) / E cup (UK)

Note that US and UK cup labeling differs starting from DD. The actual cup volume remains the same only the label changes.

Sister Sizes

Sister sizes are alternative bra sizes that have the same cup volume but different band lengths. For example 34C 36B and 32D are sister sizes and all have the same cup volume. If a bra in your calculated size does not fit perfectly trying a sister size can often solve the issue. The calculator shows your sister sizes so you can try alternatives when shopping.

Tips for a Perfect Fit

Even with the correct size not every bra will fit the same way. Here are some tips to ensure a good fit:

The band should sit level around your body not riding up at the back
You should be able to slide only one finger under the band
Straps should not dig into your shoulders
Your breasts should not spill over the top or sides of the cups
The center gore (between the cups) should lie flat against your chest

Frequently Asked Questions

How do I measure my bra size at home?

Use a soft measuring tape to measure two areas: your underbust (ribcage directly under your bust) and your bust (fullest part). Take the measurements while braless or in a non-padded bra. Enter them into the calculator to get your size. For best results measure yourself in front of a mirror to ensure the tape stays level.

What is the difference between US UK and EU bra sizes?

The band and cup labeling differ across systems. US and UK use the same band numbers (inches) but different cup lettering after D. For example a US DDD is the same as a UK E. EU sizing uses band numbers in centimeters (rounded to multiples of 5) and a different cup progression. This calculator shows all three so you can shop internationally with confidence.

What are sister sizes in bras?

Sister sizes are bra sizes that have the same cup volume but different band lengths. For example 34C 36B and 32D are sister sizes. Going up one band size and down one cup size (or vice versa) maintains the same cup volume. Sister sizes are useful when a bra fits well in the cup but the band is too tight or too loose.

Can I measure bra size without a measuring tape?

Yes you can use a string or ribbon and then measure it against a ruler or any object with known length like a credit card which is 3.5 inches long or a standard A4 paper. Mark the measurement on the string and count how many times your reference object fits into it.

How often should I measure my bra size?

It is recommended to measure your bra size at least once a year or whenever you experience significant weight changes pregnancy or changes in your body shape. Bra fit can also change with age and hormonal fluctuations.

Report

Bra Size