Case Converter

How to Use This Tool

1. 1

   Paste your text

   Any length, from a single heading to a full document.

2. 2

   Choose a case style

   Click one of the eight buttons. The output updates straight away, and you can switch styles as often as you like.

3. 3

   Convert lists line by line

   For Sentence case and Title Case, tick the per-line option when you paste a list of headings, so each line is treated as its own title.

4. 4

   Copy the result

   Use the Copy button, then restore any proper nouns or acronyms the conversion lowercased.

The Eight Styles and Where Each Belongs

• UPPERCASE — acronyms and short labels. Avoid for headings or body text; it reads as shouting and is measurably slower to read.
• lowercase — normalizing data before comparison, and some minimalist design systems.
• Sentence case — the default for headings and subheadings in most modern style guides, including UK publishing.
• Title Case — headlines and titles in US publishing conventions, with minor words left lowercase.
• camelCase — JavaScript variables and function names.
• PascalCase — class names and React component names.
• snake_case — Python variables, database columns and some file naming.
• kebab-case — URL slugs, CSS class names and HTML attributes.

Fixing Text Typed With Caps Lock On

The most common reason people reach for a case converter is a paragraph typed with Caps Lock on. Choose Sentence case: it lowercases everything and capitalizes the first letter of each sentence, which gets you most of the way in one click.

What it cannot know is which words should stay capitalized. Read the result once and restore names, places, brands and the word “I” where needed. For a long document, a find-and-replace for your most frequent proper nouns is quicker than fixing them one by one.

Sentence Case Versus Title Case for Headings

Both are correct; they belong to different conventions. US publishing traditionally uses Title Case for headlines, capitalizing major words and leaving articles, short prepositions and conjunctions lowercase. UK publishing and most modern web style guides use sentence case, capitalizing only the first word and proper nouns.

Sentence case has gained ground online for practical reasons. It is easier to apply consistently — Title Case rules about which minor words to lowercase are genuinely fiddly and people get them wrong — and it reads slightly faster because capitalization patterns match ordinary prose.

The thing that matters more than the choice is consistency. Mixed conventions across a site's headings look unconsidered. Pick one, apply it everywhere, and use the Title Case Converter if you go the Title Case route, since it handles the minor-word rules for you.

Case in URLs

Use lowercase, always. Many web servers treat /Page and /page as different URLs, which means mixed-case links to the same content create genuine duplicates that split ranking signals.

Even where the server normalizes case, mixed-case URLs are harder to type, harder to read aloud, and inconsistent with the lowercase convention every major site follows. For building slugs specifically, the URL Slug Generator handles lowercasing, hyphenation and character stripping in one step.

If you already have mixed-case URLs in circulation, the Bulk URL Formatter normalizes hostname casing across a list, and the URL Deduplicator collapses entries that differ only by case.

The Programming Cases

camelCase, PascalCase, snake_case and kebab-case exist because most programming languages disallow spaces in identifiers. Each community settled on a different convention, and following the local one matters more than any argument about which is better.

The one with SEO relevance is kebab-case, since it is the convention for URL slugs. Google has been explicit that hyphens are read as word separators while underscores are not — so best-running-shoes reads as three words and best_running_shoes may read as one token.

That single distinction is why kebab-case rather than snake_case is the right choice for URLs, file names for images, and anything else search engines parse.

Other Case Styles and How to Get Them

A few more styles turn up in style guides and codebases. Some can be produced here in two steps; others are better handled by a dedicated tool.

• CONSTANT_CASE (also called SCREAMING_SNAKE_CASE) — used for constants and environment variables. Convert to snake_case, then run the result through UPPERCASE.
• Capitalized Case — every word capitalized, including minor words such as “of” and “the”. This differs from Title Case, which keeps minor words lowercase.
• Title Case in a specific style guide — AP, Chicago, APA and MLA disagree on details such as whether to capitalize prepositions of four or more letters. The conversion here uses a short minor-word list that sits closest to AP; the Title Case Converter explains where the guides differ so you can check the output against yours.
• aLtErNaTiNg and iNVERSE case — novelty styles for social posts. They are not offered here, because they are unreadable to screen readers and to most people.

Changing Case in Word, Google Docs and Excel

If the text is already in a document, you may not need to paste it anywhere. Microsoft Word on Windows cycles selected text through lowercase, UPPERCASE and capitalized words with Shift+F3. Google Docs has Format → Text → Capitalization, with lowercase, UPPERCASE and Title Case options.

In Excel and Google Sheets, the formulas =UPPER(A1), =LOWER(A1) and =PROPER(A1) convert a cell. PROPER capitalizes every word, so it behaves like Capitalized Case rather than Title Case. None of these offer sentence case or the programming cases, which is where a converter earns its place.

Why UPPERCASE Hurts Readability

Lowercase letters have distinctive shapes — ascenders, descenders, varying heights — that readers use to recognize word shapes without reading letter by letter. Capitals are uniform rectangles, which removes those cues.

The practical result is that all-caps text is read measurably more slowly, and the effect compounds over longer passages. It is fine for a short label or an acronym and poor for a heading, and genuinely bad for a paragraph.

It also reads as shouting in most digital contexts, which is a tone problem separate from the legibility one.

How the Conversions Handle Edge Cases

Sentence case lowercases everything, then capitalizes the first letter of each sentence detected by terminal punctuation. It does not know your proper nouns, so names and brands need restoring by hand.

Title Case leaves minor words lowercase except when they are the first or last word. It lowercases the text first, so acronyms such as SEO or NASA come back as “Seo” and “Nasa” and need correcting by hand.

The programming cases strip all non-alphanumeric characters before joining, so punctuation and symbols are discarded rather than encoded.

All conversion happens in your browser — nothing you paste is transmitted or stored.

Frequently Asked Questions

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