US Bra Size to Japan Conversion Guide

Convert your US inch-based size into Japanese centimetre bands and streamlined cup letters. Use the chart, steps, and retailer tips to shop Japanese brands confidently.

View the conversion chartCheck sister sizes

Covers US bands 28–52 and Japanese bands 60–125 with cups AA through H.

Japan measures in centimetres

Bands appear in 5 cm steps—US 30 maps to JP 70, US 32 to JP 75, US 34 to JP 80, etc.

Single letters only

Japan removes double letters, so US DD becomes JP E and US DDD/F becomes JP F.

Check domestic size charts

Japanese retailers often display JP, EU, and US columns—confirm you’re referencing the JP column when converting.

US to Japanese band and cup mapping

Use the chart to translate the US band into centimetres and align the cup letter with Japanese notation.

US labelJP labelNotes
28A65AUS 28A becomes JP 65A once the band is converted to centimetres and double letters are removed.
28B65BUS 28B becomes JP 65B once the band is converted to centimetres and double letters are removed.
28C65CUS 28C becomes JP 65C once the band is converted to centimetres and double letters are removed.
28D65DUS 28D becomes JP 65D once the band is converted to centimetres and double letters are removed.
28DD65EUS 28DD becomes JP 65E once the band is converted to centimetres and double letters are removed.
28E65FUS 28E becomes JP 65F once the band is converted to centimetres and double letters are removed.
28F65GUS 28F becomes JP 65G once the band is converted to centimetres and double letters are removed.
28G65HUS 28G becomes JP 65H once the band is converted to centimetres and double letters are removed.
30A70AUS 30A becomes JP 70A once the band is converted to centimetres and double letters are removed.
30B70BUS 30B becomes JP 70B once the band is converted to centimetres and double letters are removed.
30C70CUS 30C becomes JP 70C once the band is converted to centimetres and double letters are removed.
30D70DUS 30D becomes JP 70D once the band is converted to centimetres and double letters are removed.
30DD70EUS 30DD becomes JP 70E once the band is converted to centimetres and double letters are removed.
30E70FUS 30E becomes JP 70F once the band is converted to centimetres and double letters are removed.
30F70GUS 30F becomes JP 70G once the band is converted to centimetres and double letters are removed.
30G70HUS 30G becomes JP 70H once the band is converted to centimetres and double letters are removed.
32A75AUS 32A becomes JP 75A once the band is converted to centimetres and double letters are removed.
32B75BUS 32B becomes JP 75B once the band is converted to centimetres and double letters are removed.
32C75CUS 32C becomes JP 75C once the band is converted to centimetres and double letters are removed.
32D75DUS 32D becomes JP 75D once the band is converted to centimetres and double letters are removed.
32DD75EUS 32DD becomes JP 75E once the band is converted to centimetres and double letters are removed.
32E75FUS 32E becomes JP 75F once the band is converted to centimetres and double letters are removed.
32F75GUS 32F becomes JP 75G once the band is converted to centimetres and double letters are removed.
32G75HUS 32G becomes JP 75H once the band is converted to centimetres and double letters are removed.

Convert your size in four steps

  1. Take accurate US measurements Measure snug underbust and bust in inches or use a US bra that already fits.
  2. Swap the band to centimetres Use the chart to find the matching Japanese band (65, 70, 75, etc.) and adjust the cup letter.
  3. Try sister sizes for fine-tuning If the converted band feels different, move one band up or down and offset with the sister cup.
  4. Review fabric and coverage Japanese bras can feature narrower wires or lighter padding—check reviews and try before keeping tags off.

Worked conversion examples

US 30DD -> JP 70E

US 30DD converts to JP 70E—centimetre band plus simplified cup.

US 32F -> JP 75G

US 32F maps to JP 75G for full-support Japanese styles.

US 34DD -> JP 80E

US 34DD becomes JP 80E, a common size for everyday Japanese bras.

US 36G -> JP 85H

US 36G translates to JP 85H, keeping equivalent volume.

Brand sizing cheat sheet

Use these retailer references when switching between US and Japanese labels.

US-based retailers

  • Nordstrom
  • Bare Necessities
  • HerRoom
  • Amazon US

Convert first when ordering Wacoal Japan or Peach John through US marketplaces.

Japanese brands

  • Wacoal Japan
  • Triumph
  • Peach John
  • Aimerfeel

Wacoal Japan, Triumph, Peach John, and Aimerfeel publish JP sizes first with limited US references.

International marketplaces

  • Rakuten Global Market
  • Amazon JP
  • Zozotown
  • YesStyle

Rakuten Global Market, Zozotown, and YesStyle offer JP labelling plus conversion charts.

Fit tips after converting

  • Expect narrow wires or shallow cups on some JP styles—sister sizes help dial in coverage.
  • Look for centimetre fit notes in product descriptions to confirm your converted band.
  • Record both your JP and US equivalents for each brand to streamline future orders.

Helpful tools

Interactive bra size calculator

Measure in inches or centimetres and generate both local and international sizes in one place.

Open

International bra size guide

Compare regional systems side by side and review conversion advice for cross-border shopping.

Open

Sister size navigator

Adjust bands tighter or looser while holding cup volume steady after you convert.

Open

US to Japanese conversion FAQ

How are Japanese band numbers measured?

Japan labels the underbust in centimetres, typically in 5 cm steps (65, 70, 75, etc.).

Do Japanese cups follow the same letters?

Japan uses single letters without double steps. DD converts to E and DDD/F converts to F before continuing upward.

What about petite frames or tall torsos?

After converting, try sister sizes to find the best strap placement and underband tension for your frame.

Where can I buy Japanese-sized bras?

Shop domestic brands through Rakuten, Zozotown, Peach John, and major department stores that ship internationally.