How to Measure Bra Size in cm: Step-by-Step Guide

Measuring bra size in cm provides precise metric measurements for better fit, especially in regions using the European or international sizing system. Accurate sizing ensures comfort, support, and health during daily activities or sports. This guide focuses on centimeter-based measurements, common for converting between systems or using metric tape measures.

Bra size combines two values: the band size (underbust circumference in cm) and cup size (difference between bust and underbust). Unlike inch-based systems, cm measurements allow direct calculation without initial conversions. You'll need a flexible measuring tape marked in centimeters, a mirror, and optionally a helper for accuracy.

Understanding the Measurements

Band size:This is the measurement around your ribcage directly under the breasts, typically ranging from 65 cm to 110 cm in even increments (e.g., 70, 75, 80). It forms the number part of the size, like 75B.

Bust size:The circumference around the fullest part of your breasts, usually wearing a non-padded bra. The difference between bust and band determines the cup:

• 10–12 cm: A cup
• 13–15 cm: B cup
• 16–18 cm: C cup
• 19–21 cm: D cup
• 22–24 cm: E or DD cup
• Add 2 cm per cup size thereafter (e.g., 25–27 cm: F or EDD).

These differences apply to most metric systems, though slight variations exist by brand.

Step-by-Step Guide to Measure Bra Size in cm

1. Prepare:Stand straight in front of a mirror wearing a thin, unpadded bra or no bra. Exhale normally to avoid inflating measurements.
2. Measure the band (underbust):Wrap the tape snugly around your ribcage, just below the breasts where the bra band sits. Keep it level and parallel to the floor. Note the measurement in cm. Round up to the nearest even number divisible by 5 if it's not already (e.g., 72 cm rounds to 75 cm). This is your band size.
3. Measure the bust:Wrap the tape around the fullest part of your breasts, keeping it horizontal and not too tight. Arms down at sides. Record in cm.
4. Calculate cup size:Subtract band from bust measurement. Use the difference to find the letter (see table above). Example: Bust 92 cm, band 75 cm → 92 - 75 = 17 cm → C cup. Final size: 75C.
5. Verify fit:Try on bras in your calculated size. The band should sit level without riding up; cups should cover fully without gaping or overflow.

Practical Examples

Example 1:Underbust measures 68 cm → rounds to 70 cm band. Bust 88 cm → 88 - 70 = 18 cm → C cup. Size: 70C.

Example 2:Underbust 82 cm → 85 cm band. Bust 102 cm → 102 - 85 = 17 cm → C cup. Size: 85C.

These examples use the common European method. For US/UK conversions, differences may shift cups by 1–2 sizes due to rounding practices.

Common Mistakes to Avoid

• Measuring over thick clothing or padded bras, which adds false volume.
• Pulling tape too tight on underbust (snug, not pinching) or too loose on bust.
• Not rounding band correctly—stick to standard increments like 65, 70, 75 for availability.
• Ignoring torso shape changes (e.g., measure monthly if weight fluctuates).
• Confusing systems: cm differences are tighter than inches (1 inch ≈ 2.54 cm, so 1-inch cup gap = ~2.5 cm).

In engineering or design contexts, such as custom garment prototyping, precise cm measurements integrate with CAD software for scalable patterns. Students in fashion design or ergonomics courses benefit from consistent metric sizing.

Quick Summary

To measure bra size in cm, take snug underbust and full bust measurements, subtract for cup difference, and round band to standard cm values. Repeat every 6–12 months for changes. For instant conversions between cm and inches—or other units related to clothing measurements—use the free tool at HowToConvertUnits.com.