Text Case Converter
Free text case converter online — convert to UPPERCASE, lowercase, Title Case, camelCase, PascalCase, snake_case, and kebab-case instantly. No signup, works on any device.
Title Case Is Not One Rule
Most case conversions are mechanical. Upper, lower and toggle case apply a fixed transformation to every character and there is nothing to disagree about. Title case is different: it depends on which style guide you follow, and the major guides genuinely disagree.
| The question | One convention | Another convention |
|---|---|---|
| Short prepositions such as "with" | Lowercase | Capitalise anything over three letters |
| The word after a colon | Always capitalised | Only if it begins a full clause |
| The second half of a hyphenated word | Capitalised | Lowercase unless it is a proper noun |
| The last word of a title | Always capitalised, whatever it is | Treated like any other word |
Because of this, no automatic title case is correct for every house style. The useful approach is to convert first and then read the result, correcting the few words your own style treats differently. Consistency within one publication matters far more than matching any particular guide.
What Each Case Is Actually For
Sentence case capitalises the first word and proper nouns, and nothing else. It is the easiest to read and the hardest to get wrong, which is why most modern interfaces and many publications use it for headings.
Title case capitalises the significant words. It reads as more formal and is standard for book titles, article headlines and academic references.
Upper case works for short labels and acronyms. In longer runs it is genuinely harder to read, because capital letters share a uniform rectangular outline while lower case letters have ascenders and descenders that give words a recognisable shape.
Lower case is useful for normalising data before comparison, and for the deliberate informality some brands adopt.
Converting Loses Information
This is the trap that catches people editing existing text. Converting to upper or lower case discards the original capitalisation, and no conversion back can restore it.
Take a sentence to upper case and back to lower and every proper noun, every acronym and the sentence-initial capital are all gone. The text reads as lower case throughout, and restoring it means retyping the names by hand.
Acronyms are the most visible casualty. Convert a paragraph containing NASA, PDF or URL to lower case and no automatic conversion will bring them back — title case will produce Nasa, Pdf and Url, which is worse than either extreme. Keep an unconverted copy before transforming anything you cannot easily retype.
Case in Data, Not Just Prose
Case conversion is used as often for tidying data as for writing, and the considerations are different.
- Comparing values. Converting both sides to lower case before comparing makes matching case-insensitive, which is usually what you want for names and email addresses.
- Email addresses. The domain half is case-insensitive and safe to lowercase. The local part technically is not, though in practice virtually every provider treats it as such.
- Identifiers and codes. Some are genuinely case-sensitive — API keys, passwords, base64 strings — and normalising them silently breaks them. Never case-convert a value you did not generate.
- Accented characters. Case conversion of non-English text follows language-specific rules that a simple transformation may not implement correctly, so check results in any language you cannot read.
Choosing One and Sticking to It
The most common real-world problem is not choosing the wrong case but mixing several. A page with some headings in title case, some in sentence case and one in capitals looks careless even when every individual choice was defensible.
Decide once, per element type: headings one way, buttons another, navigation a third if you like — and then apply it everywhere. Readers never notice consistent styling and always notice inconsistent styling, which is the whole argument for writing the rule down.
To check length after converting, the word and character counter gives exact counts, which matters because case conversion never changes character count even though capitals occupy more visual width.