Full-width letters
ABC becomes ＡＢＣ. These are different Unicode characters even though the letters are recognizable.
FULL-WIDTH / HALF-WIDTH CONVERTER
Make your text fit the form’s rules.
Convert arbitrary text between the character-width formats Japanese websites commonly require.
2
Copy the width you needCharacters without an equivalent are preserved
ＡＢＣ１２３ テスト
Latin letters, numbers, spaces, punctuation, and half-width Katakana are converted where supported.
ABC123 ﾃｽﾄ
Full-width Latin characters and Katakana are narrowed where a standard half-width form exists.
Your text stays in this browser. It is not saved, uploaded, or included in analytics.
全角・半角 CONVERTER
Why won’t a Japanese website accept my text?
The text can look correct while using the wrong underlying width. If the form says 全角, use full-width; if it says 半角, use half-width.
Half-width Katakana
テスト becomes ﾃｽﾄ. Not every Japanese character has a half-width equivalent.
Spaces count too
A normal space and a full-width Japanese space are different characters and can trigger validation errors.
Help and examples
Full-width and half-width characters can look similar but have different Unicode values. Japanese websites may reject the wrong width even when the text looks correct.
Example: ABC123 ﾃｽﾄ → ＡＢＣ１２３ テスト (full-width)
Common mistakes
- Forgetting that spaces also have full-width and half-width forms
- Using half-width Katakana when the form asks for 全角カタカナ
- Converting Japanese characters that have no standard half-width equivalent
Questions
Are full-width characters just a font style?
No. They are different characters, so a form can validate their width independently of how they look.
Does half-width always mean Latin letters?
No. Half-width forms also exist for numbers, punctuation, spaces, and a limited Katakana set.