cup size calculator cm

What this cup size calculator in cm does

This tool helps you estimate your bra size using metric measurements. It calculates:

• An estimated EU band size (rounded to the nearest 5 cm)
• An estimated UK/US band size (rounded to the nearest even number in inches)
• An estimated cup letter based on the difference between bust and underbust

If you have ever felt confused by bra labels, you are not alone. Bra sizing varies between regions and brands, so getting an estimate in centimeters is a practical place to start.

How to measure correctly (in centimeters)

1) Underbust measurement

Wrap a soft measuring tape around your ribcage directly under your bust. Keep it level all the way around, and keep it snug but not painful. Breathe normally and record the value in cm.

2) Full bust measurement

Measure around the fullest part of your bust. Keep the tape parallel to the floor and avoid pulling too tight. Record in cm.

Measurement tips for better accuracy

• Measure while wearing a non-padded bra (or no bra if preferred).
• Stand upright and keep the tape level front and back.
• Take each measurement twice and use the average if needed.
• Use centimeters only for this calculator.

How cup size is estimated from cm

Cup size is based on the difference:

Cup difference = Full bust (cm) - Underbust (cm)

Larger difference generally means a larger cup letter. The following chart shows the approximate range used by this calculator:

Bust - Underbust Difference (cm)	Estimated Cup
Up to 8 cm	AA
8.1 - 10 cm	A
10.1 - 12 cm	B
12.1 - 14 cm	C
14.1 - 16 cm	D
16.1 - 18 cm	DD / E
18.1 - 20 cm	F
20.1 - 22 cm	G
22.1 - 24 cm	H
24.1 - 26 cm	I
26.1 - 28 cm	J
28 cm+	K+

Quick examples

• Underbust 74 cm, bust 86 cm: difference is 12 cm, estimated cup B/C range, band around EU 75.
• Underbust 80 cm, bust 97 cm: difference is 17 cm, estimated cup around DD/E, band around EU 80.
• Underbust 68 cm, bust 82 cm: difference is 14 cm, estimated cup around C/D, band around EU 70.

EU, UK, and US sizes: why labels differ

One of the biggest challenges is that size labels are not universal. A size in one region may use different numbers and cup progression in another. This calculator gives both an EU and UK/US band estimate to make shopping easier.

• EU sizing: typically uses band numbers like 65, 70, 75, 80, 85...
• UK/US sizing: often uses even band numbers like 30, 32, 34, 36...
• Cup systems: may include letters like DD, FF, GG depending on brand and region.

Fit check after you calculate

Band fit

The band should feel firm and level around your torso. If it rides up your back, it may be too loose.

Cup fit

Your breast tissue should sit comfortably in the cup without major spillage or gaping. Minor differences can happen because cup shape varies across designs.

Straps and comfort

Straps should support but not dig in. Most support should come from the band, not the straps alone.

Common mistakes to avoid

• Using inches in a cm calculator input field
• Measuring over thick clothing
• Pulling the tape too tight around the bust
• Assuming all brands fit exactly the same
• Ignoring comfort in favor of the label only

FAQ

Is this calculator 100% accurate?

No calculator is perfect. It provides a reliable starting point, but final fit always depends on brand cut, cup shape, and personal comfort.

How often should I re-measure?

Re-measure every 6-12 months, or sooner if your body has changed due to weight shifts, training, pregnancy, or hormonal changes.

What if I am between two sizes?

Try both. Sister sizes can help: one band up and one cup down, or one band down and one cup up.

Final note

A bra size is a tool, not a judgment. Use this cup size calculator in cm to get a confident starting point, then prioritize comfort and support when choosing your final size.