A case converter with precisely stated rules

This tool converts text between three cases: Title Case, capitalizing the first letter of every word; UPPERCASE, capitalizing every letter; and lowercase, capitalizing none. Each mode applies one consistent rule across the entire input, with no exceptions beyond what's documented below.

Conversion runs entirely client-side, in JavaScript, in your browser. There is no upload and no server round trip, and accordingly no run limit.

One choice, nothing else to configure.

Step 1

Paste the text into the input field.

Step 2

Select Title Case, UPPERCASE or lowercase.

Step 3

Read the converted result.

Title Case here lowercases the entire input first, then capitalizes the first letter of every word boundary it detects. This is a single, consistent rule with no editorial exception layered on top, and it's worth being precise about how it diverges from a style guide's convention.

AP and Chicago style both capitalize major words while keeping short connecting words, a, an, the, and, or, of, in, lowercase mid-title. This tool applies no such distinction: every word's first letter is capitalized regardless of length, so 'a tale of two cities' becomes 'A Tale Of Two Cities' rather than the conventionally styled 'A Tale of Two Cities'. Where the small-words convention is required, the connecting words need a manual pass after conversion.

Because the entire input is lowercased before capitalization is applied, an acronym typed in capitals loses that capitalization. NASA becomes Nasa; USA becomes Usa. The algorithm has no concept of a recognized abbreviation, only of word boundaries, so acronyms require a manual fix after conversion.

Contractions carry a second, sharper quirk: the character immediately following an apostrophe also satisfies the word-boundary condition that triggers capitalization, so don't can convert to Don'T rather than Don't, with the letter after the apostrophe capitalized alongside the word's actual first letter. Review contractions in the output before using it anywhere reader-facing. The same applies to possessives: a name like O'Brien can come out with an unexpected capital after its apostrophe too, for the identical reason.

UPPERCASE and lowercase apply a uniform, character-by-character conversion with no word-boundary logic at all, so neither exhibits the acronym or apostrophe behavior Title Case does. UPPERCASE suits headers, labels and acronyms intended to stand out; lowercase suits normalizing text ahead of a case-insensitive comparison.

Both are, in that sense, the more predictable of the three modes: what goes in as a letter is simply converted, with no exceptions to account for.

A username, tag or identifier typed in inconsistent case can fail to match itself in a system treating case as significant. Headlines pulled from disparate sources arrive in a mix of conventions, sentence case here, all caps there, and a page where every heading follows a different rule reads as visibly unpolished.

In data work, casing drift across values that should be identical, 'Product' versus 'product' versus 'PRODUCT', is a frequent, quiet cause of a group-by or a count operation returning more distinct categories than actually exist.

Editorial teams convert a batch of headlines or titles to a single consistent style ahead of publication. Engineers normalize user input, tags or labels to one case before storing or comparing them.

It's also the fastest remedy for text entered entirely in caps lock by accident, or a list of names imported from a spreadsheet with no consistent capitalization to begin with.