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Published by SMCS AI Factory · Content reviewed:
Case converter online — UPPERCASE, lowercase, Title Case
Convert to UPPERCASE, lowercase, Title Case, camelCase, snake_case and more.
Your text
Transforms
All processing stays in your browser. Counts use Unicode code points for characters; words are letter/number sequences. Title and sentence case are heuristics, not full linguistic rules.
Transforms run in your browser. Nothing is uploaded.
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Word and character counter, case converter, slugify — free in the browser.
Device Info
Overview: battery, network, and hardware — with links to specialized tools.
Fourteen transforms, and what each one decides
Every conversion here is a pure function of your text — same input, same output, no model and no guessing. The interesting part is not upper and lower case; it is the six programmer cases, where the tool has to decide where one word ends.
Upper, lower, title, sentence, camel, pascal, snake, kebab, constant, invert, reverse, slug, collapse spaces and trim lines. Everything runs in the page, on the text you paste, and nothing is sent anywhere.
Converting a string safely
Paste the text: One string or a whole block; every transform handles both.
Pick a transform: Start with the case you need, not the one that looks closest.
Check the edge cases: Look for brand names, accents and anything that expanded.
Copy the result: Take the output away; nothing is kept once the tab closes.
Uppercase is not a one-to-one operation
Most people assume case conversion swaps letters and keeps the length. It does not always: the German sharp s becomes two letters when uppercased, and this page follows that rule rather than inventing its own.
Case is also locale-sensitive at the runtime level, which is why the same string can uppercase differently on a machine configured for Turkish. Any tool claiming a single universal answer is hiding something.
Choosing the right transform
- Title case lowercases the rest of every word, so iPhone becomes Iphone — that is the rule, not a bug.
- Slug strips accents before hyphenating: Ação e Coração becomes acao-e-coracao.
- The programmer cases split camelCase first, so converting between them round-trips cleanly.
- Constant case is snake case uppercased, which is why it inherits the same word splitting.
- Collapse spaces flattens runs of spaces and tabs but leaves your line breaks alone.
- Trim lines removes leading and trailing whitespace from every line at once.
How a word boundary is found
For the programmer cases the text is normalised before it is rebuilt: apostrophes are dropped, a lowercase-to-uppercase transition is treated as a boundary, an acronym followed by a capitalised word is split, and spaces, underscores, dots, slashes and hyphens all separate.
That is why meuNomeAqui becomes meu_nome_aqui, and meu-nome-aqui becomes meuNomeAqui. Both directions are asserted by tests in our repository.
What slug does to accents
The slug transform decomposes the text, discards combining marks, lowercases, and replaces every run of non-alphanumeric characters with a single hyphen before trimming the ends.
That produces URL-safe output for Portuguese and other accented languages without a lookup table. It also means information is lost on purpose: acao and ação collapse to the same slug, which is what a URL wants and not what a database key should rely on.
The transforms that are not case changes
Invert swaps the case of each letter individually and leaves anything caseless untouched. Reverse walks the string by code point, so accented text and simple emoji survive it intact — though a family emoji built from joiners will not.
Collapse spaces and trim lines are whitespace tools that happen to live here because they solve the same problem: text pasted from somewhere else arriving in the wrong shape.
When to stop converting by hand
Converting one string in a browser tab is fine. Converting hundreds on every save belongs in your editor or your formatter, where it is a rule rather than a chore — a tab you keep open is a sign the job moved upstream.