Uppercase & lowercase
The Upper and lower case tool instantly converts your text into four writing styles: UPPERCASE, lowercase, Sentence case and Capitalize Each Word. It is handy for tidying headings, fixing text typed with Caps Lock, unifying style and preparing titles. Everything runs locally in your browser — no text is ever uploaded and no sign-up is required.
How the upper and lower case converter works
The tool takes the text from the top box and applies one of four transformations depending on which button you press. The result is written to the read-only box below, ready to copy. Your original text stays untouched, so you can quickly try several modes one after another.
- UPPERCASE — turns every letter into a capital (the
toUpperCasefunction). Digits and punctuation stay unchanged. - lowercase — turns every letter into a small letter (the
toLowerCasefunction). - Sentence — first lowercases the whole text, then capitalizes the first letter at the start and after every period, question mark or exclamation mark. The result reads like ordinary sentences.
- Each Word — also lowercases everything first, then capitalizes the first letter of every word (title case). A word is a continuous run of letters and digits, so words separated by a space, hyphen or slash are processed independently.
The conversion handles characters according to the Unicode standard, so it correctly capitalizes accented letters too — č becomes Č, ř becomes Ř, and so on. It is not a spelling or grammar checker: the tool mechanically changes letter case and does not recognise proper nouns, acronyms or sentence starts inside quotation marks.
How to use Upper and lower case
- Type or paste the text you want to change into the top box.
- Click one of the four buttons for the style you need: UPPERCASE, lowercase, Sentence, or Each Word.
- The result appears in the lower box — select it and copy it (Ctrl/Cmd + C).
- For a different style, click another button; the tool always starts from the original text at the top.
Example of converting the input hello WORLD. how are you?:
| Mode | Result |
|---|---|
| UPPERCASE | HELLO WORLD. HOW ARE YOU? |
| lowercase | hello world. how are you? |
| Sentence | Hello world. How are you? |
| Each Word | Hello World. How Are You? |
What upper and lower case conversion is good for
It is most appreciated by people who work with text: editors and copywriters unifying headings, students fixing an accidentally engaged Caps Lock, shop managers normalising product names, or developers and marketers preparing titles and captions. The Sentence mode is ideal for quickly tidying a paragraph pasted in ALL CAPS, while Each Word suits English headings and titles.
Because the whole conversion runs directly in your browser, it is also suitable for sensitive or confidential text — notes, internal documents, personal data. Nothing is sent to a server, so the content never leaves your device. Tip: for English headings, remember that Each Word mode also capitalizes short words like "a", "the" or "of", which does not always match typographic style rules; check the result after converting.
FAQ
Does the tool handle accented and non-English letters?
Yes. The conversion follows the Unicode standard, so it also correctly changes accented letters — for example <code>č</code> ↔ <code>Č</code> or <code>ř</code> ↔ <code>Ř</code>.
What is the difference between Sentence and Each Word mode?
Sentence mode capitalizes only the first letter at the start and after a period, question mark or exclamation mark, so the text reads like normal sentences. Each Word mode capitalizes the first letter of every word (title case).
Is my original text preserved?
Yes. The top box is not changed by the conversion; the result is written separately to the lower box. This lets you try several modes in a row.
Is my text sent to a server?
No. The entire conversion runs directly in your browser using JavaScript. No text leaves your device and no sign-up is needed.
Will it fix capitalization of proper nouns?
No. The tool mechanically changes letter case and does not recognise proper nouns, brands or acronyms. In Sentence mode, for example, "london" stays lowercase unless it begins a sentence.
Why do Sentence and Each Word modes lowercase everything first?
For a consistent result. If the input had RaNdom capitals, they are first unified to lowercase and only the correct letters are then capitalized — otherwise stray capitals would remain stuck inside words.
Is there a limit on text length?
Practically no. The text is processed locally, so it only depends on your device's performance. It converts ordinary paragraphs and longer documents instantly.
How do I copy the result?
Click into the lower box, select the text (Ctrl/Cmd + A) and copy it (Ctrl/Cmd + C). The box is read-only, so you cannot overwrite the result by mistake.
📅 Last updated: 16 July 2026