Bra Size Calculator (US, UK & EU)

Enter bust and underbust to get band, cup, and sister sizes—US/USA and UK labels, with EU included.

Need steps first? How to measure with a tape

Quick answers before you calculate

Common bands are 32, 34, 36, and 38. A size like 34B pairs the band with a cup letter. Numbers match the conversion chart; brand cuts still vary.

US/UK 32 band≈ EU 70 · JP 70Common smaller band
US/UK 34 band≈ EU 75 · JP 75Very common US band
US/UK 36 band≈ EU 80 · JP 80Often ≈ EU 80
US/UK 38 band≈ EU 85 · JP 85Larger everyday band

Common sizes (US → UK / EU)

32BUK 32B · EU 70BSisters: 30C, 34A
34BUK 34B · EU 75BSisters: 32C, 36A
36CUK 36C · EU 80CSisters: 34D, 38B
38DUK 38D · EU 85DSisters: 36DD, 40C

Bra size calculator →How to measure →Full bra chart →US ↔ UK cups →

Bra Size Chart (US / UK / EU)

Full bra size chart →

Quick reference for common band and cup sizes. Use the calculator below for your exact fit.

US	UK	EU	Band (cm)
32B	32B	70B	68
34B	34B	75B	73
36C	36C	80C	78
38D	38D	85D	83

Measurements

Unit

Display

Under bust (in)

Bust standing (in)

Bust leaning (in)

Quick select

Your Bra Size

Enter your measurements to calculate bra size

Measuring Guide

Measuring Steps:

Wear your best-fitting bra or no bra
Measure under bust: snug, level around ribcage

Measure bust standing: loosely around fullest part while standing straight

Measure bust leaning: around fullest part while leaning forward 90°
Keep tape measure parallel to ground

Record measurements to nearest half unit

Measure at the end of exhale for most accurate results

Bra Sister Size Chart

Sister sizes keep roughly the same cup volume while changing the band. Go down a band and up a cup (or up a band and down a cup). Brands still vary—use this as a starting point.

Your size (US)	Common sister sizes
32A	30B · 34AA
32B	30C · 34A
34B	32C · 36A
34C	32D · 36B
34DD	32E · 36D
36C	34D · 38B
38D	36DD · 40C

Example: 34C ≈ 32D ≈ 36B. If the band rides up, try a tighter sister; if cups gap, try a smaller cup sister on a nearby band.

What this calculator shows

Enter bust and underbust to get sizes in US, UK, EU, FR, and JP. Handy when the same body gets different labels abroad.

You also get sister sizes and an accuracy label (High, Medium, or Low) so you know when to try a nearby band if the first size feels tight or loose.

How the cup math works

Cup letters follow the difference between bust and underbust, aligned with common practice from European sizing notes such as EN 13402. Treat the result as a starting size—brand stretch and cut still matter.

Body measurement vocabulary often follows ISO clothing standards (for example the ISO 8559 series). See the ISO/TC 133 clothing sizing committee for official references.

Professional Measuring Tips

Best Time to Measure

• Measure in the afternoon when your body is at its largest
• Avoid measuring during menstruation when breasts may be swollen
• Take measurements while standing straight
• Measure at the end of exhale for consistency

Measuring Technique

• Use a soft measuring tape, not a rigid ruler
• Keep the tape parallel to the ground
• Tape should be snug but not tight for under-bust
• Tape should be loose for bust measurement

Soft tape measuring underbust and bust for bra band and cup size — Measure underbust snug and bust loose—then enter both in the calculator.

International Bra Size Chart (Example)

US	UK	EU	Band (cm)	Bust (cm)
32B	32B	70B	68	84
34B	34B	75B	73	89
36C	36C	80C	78	97
38D	38D	85D	83	105

Please Note: This chart is based on data from our `size-charts.json` file and serves as a general reference. Sizes can vary significantly between different brands and styles. We always recommend checking the specific size guide of the brand you are interested in.

Frequently Asked Questions

How do I use a bra size calculator?

Measure underbust and bust (standing and leaning if possible), enter the numbers, and read band and cup in US, UK, and EU. Then check sister sizes if the band or cup needs a small adjustment.

Is this a USA and UK bra size calculator?

Yes. Results include US and UK labels (and EU and other standards). UK cup letters can differ from US on some larger cups—compare the letter shown for each region.

How do I convert bra size EU to US?

EU band numbers track underbust in cm steps (70, 75, 80…). EU 75 often starts near US 34; EU 80 near US 36. Cup letters are a starting point only—use the calculator and confirm on the brand chart.

What is 80B bra size in US?

EU 80B often maps near US/UK 36B as a starting point. Brand cuts vary—enter your measurements or try sister sizes if the band rides up or the cup gaps.

What is bra cup size?

Cup size is the letter based on the difference between bust and underbust. A larger difference means a larger cup letter on the same band.

What does 34B mean?

34B is a common US size: band near 34 with a B cup. Sister sizes often include 32C and 36A. Confirm with your measurements.

What is 32B bra size?

32B means a US/UK band near 32 with a B cup. Sister sizes often include 30C and 34A. Measure underbust and bust to confirm.

What is DD bra size?

DD is a cup letter one step up from D on many US charts (UK labeling can differ at larger cups). Volume still depends on the band—34DD is not the same as 38DD.

What are sister sizes?

Sister sizes are different bra sizes that hold the same cup volume. For example, 34C, 32D, and 36B are sister sizes. If the band or cup feels off, try the sister sizes.

How often should I measure my bra size?

Remeasure every 6–12 months, or after major weight change, pregnancy, or other body changes that affect the bust or ribcage.

Do bra sizes vary between brands?

Yes. Cuts and stretch differ by brand and style. Use the calculator as a starting size, then check the brand chart and try sister sizes if needed.