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Kanji Numeral & Daiji Converter (Japanese)

This tool converts numbers into Japanese daiji (壱, 弐, 参…, the formal anti-fraud numerals used on gift envelopes, contracts and receipts) and standard kanji numerals (千二百三十四…). It's specifically for Japanese-language numeral conventions. Everything runs in your browser — nothing is ever sent anywhere.

Supports integers from 0 to 9,999,999,999,999,999.

Your input is processed entirely in your browser and is never sent anywhere.

How to use

  1. Enter the number you want to convert (digits only).
  2. The daiji (壱弐参…) and standard kanji numeral (千二百三十四…) forms appear automatically.
  3. For a gift envelope, check "Format as a gift-envelope amount" to get the 金〜円也 form. Use the copy button to copy a result.

How it works

What is daiji?

Daiji (大字) are the formal variants of Japanese numerals — 壱, 弐, 参, 拾 and so on — used in place of the simple characters 一, 二, 三, 十. Because 一, 二, 三, 十 are so simple that a stroke could be added to alter them after the fact, daiji are used on gift envelopes (ご祝儀袋), receipts, contracts and property registrations to make the amount tamper-resistant.

Conversion rule

The input number is split into 4-digit groups (ones, 万/man, 億/oku, 兆/chō) and each digit is mapped to a character.

  • Daiji: digits 1-9 use 壱・弐・参・肆・伍・陸・漆・捌・玖, and the place values 10/100/1,000/10,000 use 拾・佰・仟・萬. In keeping with daiji's anti-fraud purpose, the leading "1" is never omitted — for example, 100,000 is written 壱拾万 (with 壱 before 拾), not just 拾万.
  • Standard kanji numerals: digits 1-9 use 一・二・三・四・五・六・七・八・九. When the digit at the ten/hundred/thousand place is 1, the leading 一 is omitted, following ordinary Japanese numeral convention (1,000 is 千, not 一千). The 万/億/兆 place values keep the leading 一 (一万, not 万), also following ordinary convention.
  • Zero is written 零.

Supported range

Integers from 0 up to 9,999,999,999,999,999 (16 digits) are supported. Negative numbers and decimals are not supported, since there's no real-world convention for writing them in daiji or formal kanji numerals for documents.

Gift-envelope format (金〜円也)

Turning on "Format as a gift-envelope amount" wraps the daiji output with 金 and 円也 (for example, 10000 becomes 金壱萬円也) — the conventional way to write an amount on a Japanese gift envelope.

What data is sent

All conversion happens entirely in your browser. Nothing you type is ever sent to a server.

FAQ

Is the number I enter sent anywhere?

No. All conversion happens entirely inside your browser, and nothing is transmitted to any server or external API.

What is daiji, and why use 壱・弐・参 instead of 一・二・三?

Daiji are formal variants of Japanese numerals used because simple characters like 一, 二, 三, 十 can be altered by adding a stroke after the fact. Daiji are used for amounts on gift envelopes, receipts, contracts and property registrations to prevent tampering.

How is 100,000 yen written in daiji?

As 壱拾万円. Standard kanji numerals write it as 十万円 (omitting the leading 一), but daiji never omits the leading 壱 for 拾, 佰, 仟 or 萬, since the whole point of daiji is to be unambiguous.

Can I convert negative numbers or decimals?

No. Daiji and formal kanji numerals are used for writing document and gift amounts, and there's no established convention for negative or decimal values in that context, so this tool only supports non-negative integers.

What's the largest number this tool supports?

Integers from 0 up to 9,999,999,999,999,999 (16 digits, i.e. up to 9999兆). Units larger than 兆 (like 京) aren't used in everyday documents, so they're out of scope.

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