Japan tools and calculators
These pages check or calculate against Japan's published formats and rules.
This hub lists the 4 tools on TNAADO Tools that are specific to Japan. The largest groups are Calculators (2) and Canadian Tools (2). Every page is free, runs in your browser and names the rule or register it uses, so you can check the source before relying on the number.
Calculators · 2 tools
Amazon Japan FBA Calculator: 販売手数料 and Fees
Amazon Japan FBA calculator: 販売手数料 referral fee by category, FBA 配送代行手数料 by size tier, 10% consumption tax and profit per unit.
Amazon.co.jp seller fees Enter the price your buyer pays, pick the FBA size tier and your category. The tool applies the tiered referral fee to the tax-inclusive total and shows profit per unit in yen.
Japanese Bra Size Converter to US, UK, EU
Convert a Japanese bra size (band in cm such as 70C, plus cup letter) to US, UK, EU, French and Australian sizing, with the Japanese cup-step caveat…
Clothing · Sizing Japanese labels use a centimetre band like the EU scheme (65, 70, 75) plus a cup letter. The letter step is not identical to EU, which is why this is a conversion rather than a fit promise. Conversion conventions, checked October 2, 2026. A…
Canadian Tools · 2 tools
Japan My Number Validator – Format & Checksum Check | TNAADO
Free Japan My Number (マイナンバー) check digit validator. Checks the 12-digit format and mod 11 digit in your browser. Checksum only: cannot confirm…
International · Validation マイナンバー（個人番号）チェックデジット検証 Check that a 12-digit My Number (個人番号) has the right check digit in its last position. Format and checksum only. Everything runs in your browser. How it works: the first 11 digits are multiplied by fixed…
法人番号 チェックデジット 計算・検証ツール
法人番号（13桁）のチェックデジットを計算・検証する無料ツール。12桁の基礎番号から検査用数字を計算し、13桁の番号を確認します。形式とチェックデジットのみの確認で、法人が実在するかは確認できません。入力内容は送信されません。
International · Validation 13桁の法人番号の検査用数字（チェックデジット）を、12桁の基礎番号から計算し、番号が正しい形式かを確認します。形式とチェックデジットのみの確認です。すべてブラウザ内で処理されます。 Japan Corporate Number (法人番号) check digit calculator and validator. Format and checksum only. 計算方法: 12桁の基礎番号について、最下位から偶数桁の和を2倍し、奇数桁の和を加えた値を…
Why these tools are listed under Japan
A tool is placed under Japan when its address or title names the place, as with Amazon Japan FBA Calculator and Japan My Number Validator – Format & Checksum Check, or when it sits in a section built for that country. The same tag is written into each page's structured data as the place it covers, so search engines and assistants can tell which rules a result was built for. Generic tools such as unit converters carry no jurisdiction and are not listed. Rates and thresholds change, so check the dated source on each tool before filing, paying or signing anything.