Fullwidth Digit Three

Switch a Japanese input method to full-width alphanumeric mode.

On Windows, Microsoft Japanese IME, the Japanese text input tool, offers full-width alphanumeric mode; F9 converts selected text to full-width alphanumeric, and F10 to half-width. On Mac, Japanese input settings include “Full-width numeral characters”; type the number in that mode. As of 2026, these are input-mode choices, not font styling.

Why is ３ wider than 3?

It is the same number in a wider compatibility form.

In older mixed-width East Asian text systems, characters in double-byte encodings (two bytes per character) occupied two display cells, while ASCII (the basic Latin character set used in computing) occupied one. A wide digit could line up with Japanese kana and kanji. Unicode preserves both forms so older text can retain the characters it used. The Japanese terms are zenkaku (全角, full-width) and hankaku (半角, half-width); the same width distinction also appears in Chinese and Korean computing. The Japanese standardization trail reaches JIS C 6226, a Japanese character-encoding standard, in January 1978; it was renamed JIS X 0208 in 1987. The form developed through encoding standards; it was not a new numeral.

Will ３ work in a form that accepts 3?

Not always: it has the same value, but it is a different character.

Unicode compatibility normalization, a text-cleanup step that folds some alternate forms, can convert ３ to ordinary 3. A strict identifier, database field, or search can still distinguish them until that cleanup happens.