Making text uppercase takes no thought until you hit one of the odd cases, so most of this page is about those. The basic job is simple: paste your text above and every letter that has a capital form is converted.
When uppercase is the right choice
Short labels, warnings and headings, where the shape of the word does the work: STOP, DANGER, SALE ENDS SUNDAY. Table headers in a plain-text report. Constants and environment variable names in code, though for those the CONSTANT_CASE converter also swaps spaces for underscores. Ticket or reference codes that should be typed the same way every time. Legal documents and contracts have traditionally put key clauses in capitals, such as disclaimers of liability, though plain language guidelines now advise against it.
It is the wrong choice for long text. A block of capitals is noticeably slower to read because all the words have the same silhouette, and online it reads as shouting. If you want a headline that looks formal without the shouting, title case is the better route; our short note on title case versus sentence case goes into why.
What happens to accents and other alphabets
Accented letters keep their accents: é becomes É, ñ becomes Ñ. Greek, Cyrillic, Armenian and other alphabets with two cases are converted as well. Scripts that have no capitals, such as Chinese, Japanese, Arabic and Hebrew, pass through unchanged.
A few conversions change the length of the text, which is worth knowing if a character limit matters. The German ß becomes two letters, SS, so “Straße” is six characters but “STRASSE” is seven. Some ligatures expand the same way, for example the “fi” ligature becomes FI.
The Turkish and Azeri alphabets have a dotted capital İ and a dotless lowercase ı. The tool follows the standard rules rather than any one language, so a plain “i” becomes “I”, not “İ”. Text in those languages needs a quick check.
Handy to know
Numbers and punctuation do not change, and neither do emoji. Spaces and line breaks stay exactly as they were, so a pasted list keeps its layout. The text is converted live, so you can edit the box and watch the result follow.
If you are after the opposite, there is a lowercase converter. To see every common style at once, including uppercase, camelCase and snake_case, the case converter shows them side by side. For text where only the first letter of each sentence should be capital, use sentence case.