Fullwidth Digit Zero

Its value is zero; fullwidth describes its text width.

The earliest documented milestone for this East Asian fullwidth convention is Japan's 1978 JIS C 6226, a character standard that assigned two bytes of computer storage to each character. It let Latin letters and digits occupy square cells alongside Japanese text. Later character sets carried that grid forward. Unicode keeps ０ as a compatibility form corresponding to ASCII 0, preserving the distinction for text laid out with fullwidth characters.

When should I use ０ instead of 0?

Use it only when the layout or field asks for fullwidth digits.

In Chinese, Japanese, and Korean text, fullwidth digits can align with the square cells used by many characters. Japan's e-Gov application data specification lists 全角数字 as a separate character-type check as of 2026.

Use ASCII 0 for URLs, IDs, source code, and other machine-facing numbers unless the receiving field says otherwise. In 2025, a WebKit issue documented work to normalize fullwidth digits in browser number fields and noted that browser engines could behave differently.

How do I type the wide zero?

Choose fullwidth or zenkaku mode in a Japanese IME.

A Japanese IME (input method editor) can switch between halfwidth and fullwidth numerals. As of 2026, Google Japanese Input and Apple's Japanese input guide document separate width settings for numerals.

As of 2026, the macOS Japanese input source offers a “Full-width numeral characters” setting for number keys. If an editor has no IME mode, use its Unicode character-entry command. The assigned width does not guarantee a visibly wide outline: fonts and layout can alter what appears on screen.