Uppercase and lowercase converter

Choose the change your text actually needs

An uppercase and lowercase converter changes the letters in a piece of text without rewriting its message. Use it when a heading arrives in capitals, a list needs a consistent appearance, or you want to capitalize the beginning of a short note. Paste the original text, select one of the five modes and press Convert. The result appears separately, so you can compare it with the source before copying it elsewhere.

The important decision is how much of the original capitalization to replace. Uppercase and lowercase affect every letter that has a corresponding form. Sentence case and Title Case first make the text lowercase, then add capitals in selected positions. First letter behaves differently: it changes only the first letter it finds and leaves the rest of your capitalization alone.

This difference matters for a message containing names, product labels or abbreviations. A mode that starts by lowercasing the text can turn NASA into Nasa or nasa, depending on its position. It cannot know that those capitals carry meaning. Keep the original available and choose the narrowest change that fits your task rather than expecting a broad conversion to preserve every exception.

What the five modes do

Uppercase and lowercase

UPPERCASE changes eligible letters to capitals. Lowercase changes them to small letters. Numbers, spaces and punctuation are not removed by these modes. Accented letters keep their accents while changing case where the writing system supports it. For example, café becomes CAFÉ in uppercase, not CAFE. This is not an accent remover or a converter to plain ASCII characters.

Use uppercase for a label that must follow an all-capitals format. Use lowercase to normalize ordinary text before another editing step. Neither choice fixes spelling, changes word order or adds missing punctuation. Some Unicode case mappings can change the length of a string, so a converted text is not guaranteed to contain exactly the same number of characters as the input.

Sentence case and Title Case

Sentence case lowercases the text and capitalizes the first eligible letter at the beginning, after a line break, and after supported sentence punctuation followed by whitespace. It is a mechanical rule, not a grammar analysis. A period inside an abbreviation can look like a sentence ending, while punctuation immediately followed by another word may not create a new boundary.

Title Case also starts with lowercase text, then capitalizes the beginning of each detected word. It does not apply an editorial style guide or keep small connecting words lowercase. A heading such as a guide to the city becomes A Guide To The City. That is useful for uniform word initials, but a publication may require a different treatment of articles, conjunctions or prepositions.

First letter

First letter finds the first letter anywhere in the input and makes it uppercase. A leading quotation mark, number or space does not prevent it from finding that letter. The rest of the text stays as entered. This is the right distinction when you want to change the opening of a message without altering an acronym later in the same message.

It does not capitalize the first letter of every line or every sentence. With several paragraphs in the box, only the first eligible letter in the whole input changes. If each separate item needs its own initial capital, compare the behavior of Sentence case or Title Case instead of repeatedly assuming that First letter works line by line.

Three examples you can reproduce

Compare all modes on one short message

Use hello WORLD. next STOP! as the input. The outputs below show why choosing a mode matters more than choosing a label that merely sounds similar:

The final row preserves WORLD and STOP exactly as entered. The middle rows do not. For a real document, test a short sample containing your important abbreviations before converting the entire passage. That sample is more informative than a sentence made only of ordinary lowercase words, because it exposes the information a conversion might erase.

Keep accents while changing letters

Paste ação, café, NIÑO and select UPPERCASE. The result is AÇÃO, CAFÉ, NIÑO. Select lowercase and run the conversion again from the original input to obtain ação, café, niño. The comma separators and accents remain. This example also shows that selecting another mode does not replace the source with the previous output: each conversion uses the text in the original input box.

If you need names without accents for a separate system, that is a different transformation. Do not assume that uppercase implies unaccented text. Also check the destination's actual requirements before removing accents from names, since the accent may be part of the correct spelling rather than decorative formatting.

Understand the sentence boundary rule

With hello.world. next as input, Sentence case produces Hello.world. Next. The first period has no following whitespace, so world does not receive a capital. The second period is followed by a space, so Next does. A real line break also starts a new capitalization opportunity, even if the preceding line has no full stop.

That behavior can help with short lines copied from a list, but it may be unsuitable for a poem, an address or a paragraph broken into lines during copying. Check where your actual line breaks occur. Visual wrapping inside the input box is not the same as pressing Enter or pasting a stored newline character.

A careful workflow for headings, notes and lists

Start by deciding what the destination requires. A form asking for uppercase text has a clear mechanical requirement. A newsletter heading needs an editorial decision. A personal name needs correct spelling and conventional capitalization. Those are different tasks even when all three involve capital letters, and the converter only performs the mechanical part you select.

For a heading, paste just the heading rather than the whole article. Convert it, inspect small words and restore any brand spelling that matters. For a note typed with Caps Lock, Sentence case can provide a starting point, but proper names within sentences still need attention. For a list of labels, uppercase or lowercase creates consistent case without sorting the entries or removing repeats.

After changing the input or selecting another option, run the conversion again. The previous result is cleared when the form changes so that you do not accidentally copy an output made with older settings. Review the beginning, middle and end of a long result, especially around abbreviations, quotation marks and line breaks, before using Copy result.

The output is plain text, not a styled document. Copying from a word processor does not make this tool preserve fonts, bold text, colored headings or table layout. If your destination has rich formatting, paste the converted words into the appropriate location and apply that document's styles there. Capitalization and typography are separate editing decisions.

Names, acronyms and technical text need a final check

Case conversion cannot infer which words are personal names, cities or organizations. A lowercase starting point also loses distinctions such as iPhone, eBay or a deliberately mixed-case identifier. Title Case does not reconstruct those forms from context. When a name must be exact, compare it against your original rather than treating the generated capitalization as a correction.

Be especially cautious with passwords, API identifiers, file paths and other technical strings. Changing their letters can change their meaning or stop them from working. A URL may contain case-sensitive parts even when the hostname looks familiar. The converter has no way to distinguish a decorative heading from a value that another system will compare literally.

Apostrophes and hyphens also deserve inspection when using word initials. The tool detects words with Unicode letter rules, not a dictionary of names. An apostrophe within a detected word may remain part of that word, while a hyphen separates parts for capitalization. The result should be assessed as a consistent text transformation, not as an authoritative spelling of a compound name.

Repeated conversions do not restore information that was lost. If you lowercase a carefully capitalized paragraph, then apply Title Case, you do not get the original back. Preserve a separate copy when the source matters. The original input remains visible during ordinary conversion, but the Clear button removes the current input and result rather than creating an undo history.

Limits, copying and the next editing step

The form accepts up to 200,000 characters at a time. An empty input, or one containing only whitespace, produces a request to enter text. Very large passages should be divided at sensible paragraph boundaries, especially on a phone. Avoid splitting a sentence in the middle when using Sentence case, because each new batch begins a fresh capitalization context.

If copying is unavailable in your browser, select the output and copy it manually. The result field is read-only, so make any final editorial changes in your destination editor or revise the original input and convert again. A clipboard success message confirms the copy action; it does not confirm that the destination has accepted the text or preserved its formatting.

When the next task is removing repeated entries, use Remove duplicate lines. Its option to ignore case compares entries without forcing every retained line to lowercase. When the next task is arranging a list, use Alphabetical order. Keeping these operations separate lets you decide whether you want to change letter appearance, compare whole entries or change their sequence.