Kanji Numeral Converter (Japanese Numbers ⇔ Arabic Digits)
Convert Japanese numbers written in kanji (千二百三十四, 二〇二四) to ordinary digits (1234, 2024) and back. It also handles formal daiji numerals (壱萬弐千参百) used for amounts on contracts and receipts, and converts every number in a block of text at once. Full-width digits and comma-separated numbers are accepted. For other Japanese date formats, try the Japanese Era Converter.
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Notes
- Every kanji numeral in the text is treated as a number. Numerals that are part of a word, such as 一緒 (together) or 三日月 (crescent moon), are converted too, so check the result before using it. Sequences made only of units with no digit, such as 京都, 千葉, 十分 or 万歳, are left unchanged.
- Sequences that are not valid numbers, such as 十十 or 百十千, are left unchanged.
- Digits to kanji with units or daiji supports integers up to 24 digits (up to 垓). The digit-by-digit style has no length limit.
- Decimals are converted as an integer part and a fractional part, with 点 for the decimal point (3.14 → 三点一四).
- Contracts and invoices sometimes require a specific format for amounts. Check the recipient’s requirements before you submit.
Glossary
Unit notation vs. digit-by-digit
Unit notation writes 1234 as 千二百三十四, using the units 十 (10), 百 (100) and 千 (1,000). Digit-by-digit notation writes it as 一二三四, one kanji per digit. Years and ID numbers usually use the digit-by-digit form (二〇二四年), while amounts and counts usually use units.
Daiji (formal numerals)
Daiji are more complex characters used for numbers, such as 壱 (1), 弐 (2), 参 (3), 拾 (10) and 萬 (10,000). They make it harder to alter an amount by adding strokes, so they appear on contracts, invoices and receipts. This tool always writes 壱 even before 拾, 百 and 千 (壱拾, 壱百, 壱千).
万, 億, 兆, 京, 垓
Japanese introduces a new unit every four digits: 万 is 10^4, 億 is 10^8, 兆 is 10^12, 京 is 10^16 and 垓 is 10^20. Western numbers group digits by three, so it is easy to misplace a digit when moving between the two.
FAQ
Can I use it for amounts on contracts and receipts?
Choose "Formal daiji" under "Digits → kanji" and 12000 becomes 壱萬弐千, using 壱, 弐, 参, 拾 and 萬. Always follow the format your recipient asks for.
Will kanji numerals inside words like 一緒 be converted?
Yes. Every kanji numeral is treated as a number, including those that are part of a word, so review the result of "Kanji → digits" before using it.
Does it handle both 二〇二四 and 二千二十四?
Both become 2024. The tool supports digit-by-digit notation (〇一二三…) and notation with the units 十, 百, 千 and 万.
How large a number can it convert?
Notation with units and daiji support integers up to 24 digits, including 垓 (10^20). Digit-by-digit notation has no length limit.
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