Case Converter
Change the capitalisation of any text in one step. Paste a heading, a paragraph, or a variable name and every version appears at once — UPPER CASE, lower case, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and the two joke cases — each with its own copy button. It is the fastest fix for a sentence typed with caps lock on, a headline that needs proper title capitalisation, or a phrase that has to become a URL slug. Everything runs in your browser: no sign-up, no upload, and your text is saved on your own device so it is still there when you come back.
Saved in this browser as you type; nothing is uploaded. full word & character counts →
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
Shouting, headlines, and form labels.
the quick brown fox jumps over the lazy dog
Strips every capital — handy for cleaning pasted text.
The Quick Brown Fox Jumps over the Lazy Dog
Headlines and blog titles; short joining words stay lowercase.
The quick brown fox jumps over the lazy dog
One capital per sentence — fixes text typed with caps lock on.
theQuickBrownFoxJumpsOverTheLazyDog
JavaScript variables and JSON keys.
TheQuickBrownFoxJumpsOverTheLazyDog
Class and component names.
the_quick_brown_fox_jumps_over_the_lazy_dog
Python, SQL columns, and file names.
the-quick-brown-fox-jumps-over-the-lazy-dog
URLs, slugs, and CSS classes.
THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG
Environment variables and constants.
tHe QuIcK bRoWn FoX jUmPs OvEr ThE lAzY dOg
The sarcasm meme font.
THE quick BROWN FOX JUMPS OVER THE LAZY DOG
Flips every letter — rescues text typed with the shift key stuck.
Fixing Text Typed With Caps Lock On
If a whole message came out shouting, Sentence case rewrites it as ordinary prose: one capital at the start of each sentence, the word “I” kept upper case, everything else lowered. If only the shift key was inverted — “tHIS iS aNNOYING” — use iNVERSE cASE instead, which flips each letter rather than rewriting the sentence, so names and acronyms come back correctly.
Title Case Rules
Title Case capitalises the first and last word of a line plus every significant word in between, while short joining words — a, an, the, and, of, in, to, for, with — stay lowercase. That is the usual newsroom convention and the one most style guides for blog headlines follow. Each line is treated as its own title, so you can paste a whole list of headings and convert them in one go.
Programming Cases: camelCase, snake_case & kebab-case
The converter reads the words in your text whatever style they arrive in — spaced, camelCase, snake_case, or kebab-case — and rebuilds them in the style you pick. Use camelCase for JavaScript variables, PascalCase for classes and React components, snake_case for Python and database columns, kebab-case for URLs and CSS class names, and CONSTANT_CASE for environment variables. Converting a page title straight into a kebab-case slug is the most common use of all.
Counting, Cleaning, and Converting Together
Need the word count, a character limit check, or a clean-up pass on the same text? The word & character counter has the same case conversions built in as a tab, alongside live counts, platform limits, a word goal, and tools for removing extra spaces, stray line breaks, and duplicate lines.
Changing case in a browser tab means leaving the app you were typing in. The Synapse AI keyboard rewrites, retones, and fixes text directly inside WhatsApp, Gmail, or anywhere else on Android — select, tap, done.
Download Synapse FreeFrequently Asked Questions
How do I change text from capitals to lowercase?
Paste the text into the box and copy the “lower case” row. Nothing is installed and nothing is uploaded — the conversion happens in your browser as you type.
What is the difference between Title Case and Sentence case?
Title Case capitalises the important words in a line — used for headlines and titles. Sentence case capitalises only the first word of each sentence, the way ordinary prose is written. This converter leaves short joining words (a, of, the, and) lowercase inside a title, which is the standard AP-style rule.
Can it fix text I typed with caps lock on?
Yes — use Sentence case to rewrite it as normal prose, or iNVERSE cASE if only the shift key was inverted (so “tHIS” becomes “This”).
What are camelCase, snake_case, and kebab-case for?
They are programming naming styles: camelCase for JavaScript variables, PascalCase for classes and components, snake_case for Python and SQL columns, kebab-case for URLs, slugs, and CSS classes, and CONSTANT_CASE for environment variables. Paste a phrase in any of those styles and the converter reads it correctly.
Does it keep my line breaks?
Yes. Every conversion works line by line, so a pasted list stays a list — each line gets its own first capital where the case calls for it.
Is the case converter free?
Yes — free, no sign-up, no limits, and it works offline once the page has loaded. Your text is saved only on your own device so you can come back to it.