Kansuji Converter

Integers from 0 up to 9,999,999,999,999,999 (16 digits) are converted exactly. Kanji numerals use positional markers (十, 百, 千, 万, 億, 兆), and by convention 一 is omitted before them, so 10 is 十 rather than 一十. Daiji always spell out the digit, as in 壱拾, in keeping with their anti-tampering purpose. When reading kanji into numbers, both positional writing (一万二千) and digit-sequence writing (二〇二六) are accepted.

0 becomes 零. Negative numbers (e.g. -45) are written in kanji as マイナス四十五. Decimals (e.g. 3.14) convert the integer part positionally and the fractional digits one by one, giving 三・一四. Daiji and the money notation apply only to integers of 0 or more; negative or decimal input is marked as not applicable. Converting from kanji to numbers supports integers only.

Receipts, contracts, family registers, and commercial registrations in Japan use daiji so that 一 cannot be altered into 二 or 三 with an extra stroke. Japanese regulations for family registers and commercial registration require 一, 二, 三, and 十 to be written as 壱, 弐, 参, and 拾. For amounts of money, the customary style is 金壱萬円也: 金 in front and 也 at the end prevent digits from being added to the amount.

Daiji are complex kanji numerals such as 壱, 弐, 参, 拾, and 萬 used in place of 一, 二, and 三. Because a stroke can easily turn 一 into 二 or 三, daiji are used on receipts, contracts, and registrations to prevent tampering with amounts. Under current Japanese regulations, 一, 二, 三, and 十 must be written as 壱, 弐, 参, and 拾 in such documents.

0 becomes 零. Negative numbers are written in kanji with the prefix マイナス (minus), and decimals convert the integer part positionally and the fractional digits one by one after ・ (for example 3.14 becomes 三・一四). Daiji and the formal money notation exist to prevent tampering, so they support only integers of 0 or more; negative numbers and decimals are shown as not applicable.

No. The conversion runs entirely in JavaScript within your browser. The numbers and amounts you enter are never sent to or stored on any server.