Japanese bra sizes 2025: Calculation, conversion and fit guide

Finding the right Japanese bra sizes can be confusing, especially when comparing them with US, UK, or European standards. With unique measurements based on centimeters and a distinct sizing system, Japanese bras are known for their comfort, precision, and flattering fit. Understanding how to calculate and convert your size helps you choose lingerie that truly supports and complements your shape. 

In this guide, you’ll learn everything about Japanese bra measurements, cup conversions, and fit tips to make your shopping easier. Keep reading at Japan With Love to discover how to find your perfect Japanese bra size and shop with confidence!

1. What makes Japanese bra sizes different from Western ones?

Understanding the key differences between Japanese bra sizes and Western sizing systems helps you choose the perfect fit with confidence. Below are the main factors that set Japanese sizing apart and make it increasingly popular worldwide.

• Band size is measured in centimeters instead of inches. This provides greater precision and makes it easier to convert using a Japan bra size chart.
• Cup size increments are smaller and more detailed. Each cup increases by about 2.5 cm, offering a more refined fit than most Western systems.
• Sizing notation is written in reverse order. Japanese bras list the cup first and band second (e.g., “C70”) unlike “32C” in the US, so always check a Japanese bra size converter before buying.
• Designs are made for different body shapes. Cups are often shallower and more centered, creating a lifted, rounded silhouette that differs from Western fits and aligns closely with traditional Japanese beauty standards.
• Padding and shaping features are more common. Many Japanese bras focus on enhancing volume and providing extra support for smaller or petite frames.
• Manufacturing standards are more precise and consistent. Japanese brands are known for strict quality control, making Japanese bra measurements highly reliable.
• Global interest continues to grow. More shoppers now search for Japan bra size conversion to US or Japanese bra sizes to UK to access authentic Japanese lingerie brands.

2. How to measure your Japanese bra cup sizes?

Before checking any Japan bra size chart or using a Japanese bra size converter, you need to take accurate body measurements. The process is simple, but small mistakes can lead to the wrong size. Here’s how to prepare and measure both your underbust and full bust correctly.

Use a soft measuring tape in centimeters, a mirror, and wear a non-padded or lightly padded bra. Stand relaxed and breathe normally for the most accurate results. Maintaining overall skin and body care, often supported by Japanese beauty supplements, can also influence comfort and fit over time.

• Step 1: Measure your underbust (アンダーバスト / Andābasuto): Wrap the tape snugly around your ribcage just under your breasts. Make sure it’s level 
• Step 2: Measure your full bust (トップバスト / Toppu Basuto): Place the tape around the fullest part of your bust, keeping it straight and not too tight. Record the measurement in centimeters while standing naturally.

3. How to calculate your Japanese bra sizes?

Once you’ve taken your measurements, it’s time to find your exact Japanese bra size. The calculation includes two parts, your band size and cup size. Together, they form your full size (for example, C70 or D75).

3.1 Band size

Your band size is determined by your underbust measurement in centimeters. Japan uses round numbers like 65, 70, 75, 80, and 85 to represent band sizes.

How to pick your size:

• Round your underbust measurement to the nearest multiple of 5.
• If you’re between two sizes, choose the larger one for comfort or the smaller one for a snug fit.
• For example, an underbust of 68 cm = Band 70; 73 cm = Band 75.

Japanese band size chart:

This number is the foundation of your Japanese bra measurements, so make sure it’s correct before moving on to the next step.

3.2 Cup size

The cup size is calculated from the difference between your bust (full bust) and underbust measurements. Each cup size in Japan increases by about 2.5 cm in difference.

How to calculate:

1. Subtract your underbust measurement from your full bust measurement.
2. Compare the result (in cm) with the chart below to find your Japanese cup size.
3. Combine it with your band size, for example, a 15 cm difference with 75 cm band = C75.

Japanese cup size chart:

Example: If your bust is 90 cm and underbust is 75 cm → difference = 15 cm → C cup → Japanese size = C75.

3.3 Key tips and takeaways

Now that you know how to calculate your Japanese bra size, here are a few important points to keep in mind for the best fit and comfort, especially if you like pairing lingerie with shaping items such as stockings Japan styles for a polished look.

• Always measure in centimeters, as Japanese bra sizes are based on cm for higher accuracy.
• If your size falls between two bands, try the smaller band with a larger cup; this is known as sister sizing.
• The letter always comes before the number in Japanese sizes, for example “C70” instead of “70C.”
• Remember that fit and comfort matter more than the exact size label because different brands can vary slightly.
• When purchasing from abroad, use a trusted Japanese bra size converter to compare with US, UK, or EU sizes easily.

4. Japanese bra converter to the US, EU, and AUS

Once you know your measurements, the next step is understanding how Japanese bra sizes translate internationally. Because sizing systems differ by region, using a reliable Japanese bra size converter helps you find the right fit when shopping from global brands.

4.1 Band size

In Japan, the band size is measured directly in centimeters, while other countries like the US, UK, and Australia use inches or slightly adjusted values. To convert your Japanese band size, refer to the comparison below and choose the closest match.

Tip: Japanese bands tend to fit slightly tighter, so if you’re between sizes, consider going one size up when converting to Western brands.

4.2 Cup size

Japanese cup sizing starts at A cup and increases in 2.5 cm increments between the underbust and bust measurements. Western cup sizes often use 1-inch increments, so direct conversions may vary slightly. The table below offers a general guide to match your Japanese cup size with global equivalents.

Note: Some Japanese brands may stop at cup F or G, while Western labels may extend further. Always check each brand’s Japan bra size chart for the most accurate conversion.

Understanding Japanese bra sizes gives you a big advantage when shopping for high-quality lingerie from Japan. Once you know how to measure, calculate, and convert your size, you can enjoy the precision and comfort that Japanese brands are famous for. Whether you’re comparing Japanese bra sizes to US or UK charts or using a converter for EU or AUS, a little knowledge ensures the perfect fit every time.

FAQs - What people also ask about Japanese bra sizes

Minase Suiren

Minase Suiren is a seasoned cultural writer and lifestyle curator focusing on Japanese beauty rituals and everyday aesthetics. She holds a master’s degree in intercultural communication from Waseda University with a research focus on beauty norms and gender identity in modern Japanese media.

View articles by Minase Suiren