# Lower Case to Upper Case Converter

> A free online text case converter that changes lower case to upper case and back, and also makes sentence case, capitalized words, alternating case and inverse case, with all the work done in your browser.

This free Lower Case to Upper Case converter turns your text into capitals with one button. Paste or type your text, press UPPER CASE and copy the result. It also does lower case, sentence case, capitalized words, alternating case and inverse case. Your text is changed in your browser, and nothing is uploaded.

## Key facts

- Input: up to 200,000 characters of text; line breaks and spaces are kept, and characters that have no upper and lower case (digits, punctuation, emoji, most Chinese and Japanese characters) stay as typed.
- Output: six cases (UPPER CASE, lower case, Sentence case, Capitalize Each Word, aLtErNaTiNg cAsE, iNVERSE cASE), with Copy, Download .txt (UTF-8) and live counts of characters, characters without spaces, words and lines.
- Case rules come from your browser's built-in Unicode case mapping: the German ß becomes SS in upper case ("straße" gives "STRASSE"), the Greek final sigma is handled, and a Language rules choice (Turkish, Azerbaijani, Lithuanian) applies the dotted and dotless i pairs.
- Sentence case does not know names, the word I or abbreviations: it makes everything that is not at the start of a sentence lower case, and a full stop after an abbreviation followed by a space starts a new sentence.
- Free, with no account, no human check and no daily limit, because the text is changed on your device.

## Sources

- [Unicode Consortium: Case mapping (Unicode Standard, chapter 3.13)](https://www.unicode.org/versions/latest/core-spec/chapter-3/)

Last reviewed: 2026-10-15

## How it works

1. Type or paste your text into the box labelled "Your text". The box opens with a sample sentence, so you can replace it.
2. Press one of the six case buttons: UPPER CASE, lower case, Sentence case, Capitalize Each Word, aLtErNaTiNg cAsE or iNVERSE cASE. The page opens on UPPER CASE.
3. Read the result in the box labelled "Result:". It updates as you type or press a button.
4. Check the counts under the box: characters, characters without spaces, words and lines.
5. Press Copy to put the result on your clipboard, or press Download .txt to save it as a text file.

## How to use the Case Converter

Using the tool takes a few seconds. Type or paste your text into the box labelled "Your text". The result appears in the box labelled "Result:" as soon as you type, and you do not need a convert button.

Pick one of the six case buttons to change the result. The page opens on UPPER CASE, so the result is in capitals until you choose another button. The counts under the input box show characters, characters without spaces, words and lines.

- Press Copy to put the result on your clipboard.
- Press Download .txt to save the result as a plain text file.
- Press Clear to empty the box.

## Lower case to upper case

When you need to change lower case to upper case, press the UPPER CASE button. Every letter becomes a capital. For example, "Hello World" gives "HELLO WORLD". It works the same way for any text you paste, and you do not have to select anything first.

The same button serves as an all capital converter and a capital letter converter. People who want to convert to capital letters, or who search for lowercase to caps, are looking for this button too. Digits, punctuation and emoji stay as typed.

- "straße" gives "STRASSE" in UPPER CASE.
- The result can be longer than the input for that reason.

## Uppercase converter and capital letters

This page works as an uppercase converter for short notes, headings and lists. Line breaks and spaces are kept as typed, so your layout stays the same.

People who search for "capital letters convert" want every letter of their text to become a capital. The UPPER CASE button does exactly that. Characters that have no upper and lower case, such as digits, punctuation, emoji and most Chinese and Japanese characters, stay as they are.

## Upper case to lower case

To go the other way, press the lower case button. Every letter becomes small, so "Hello World" gives "hello world". If you search for a way to put text to lower case, or just want lowercase for a whole block, this is the button.

Greek capitals follow a special rule. A capital sigma at the end of a word becomes the final-form sigma, so "ΟΔΟΣ" gives "οδος" with the last letter ς.

## Sentence case and its limits

Sentence case makes the whole text lower case, then puts a capital at the start of the text, at the start of every line and after a full stop, exclamation mark, question mark or ellipsis that is followed by a space or a line break. For example, "hELLO wORLD. this is a test! ok? yes..." gives "Hello world. This is a test! Ok? Yes...".

A full stop inside a number or an address does not start a sentence, so "3.5" and "aiipworld.com" are left alone. Sentence case has honest limits, though. It does not know names, the word I or abbreviations. A full stop after an abbreviation followed by a space counts as the end of a sentence, so "5 p.m. now" becomes "5 p.m. Now". Fix those by hand.

## Capitalize Each Word, alternating and inverse case

Capitalize Each Word makes the text lower case, then capitalizes the first letter of every word. "don't" gives "Don't", and "well-known" gives "Well-Known". Names with a capital inside lose it, so "O'Neil" gives "O'neil".

Alternating case lets the letters take turns, small first. "hello world" gives "hElLo WoRlD". Inverse case swaps every capital and small letter, so "Hello World" gives "hELLO wORLD".

- Capitalize Each Word capitalizes small words such as of and the too, so it does not follow title case rules.
- Alternating case and inverse case do not change spaces, digits or punctuation.

## Special letters: German ß, Turkish i and Greek sigma

The German letter ß becomes SS in UPPER CASE, so "straße" gives "STRASSE". Use the lower case button afterward and you get "strasse", not "straße".

Turkish and Azerbaijani keep the dotted and dotless i apart. Choose Turkish or Azerbaijani in the Language rules drop-down to use that pairing. With Default rules, "istanbul" in UPPER CASE gives "ISTANBUL". With Turkish rules, it gives "İSTANBUL". The Lithuanian rule is for Lithuanian text only. The drop-down changes only the six case buttons. It does not translate or spell-check.

## Counts, copy and download

The counts under the box show characters, characters without spaces, words and lines. Characters are counted as Unicode characters, so an emoji counts as 1. Words are groups of characters separated by spaces or line breaks. An empty box shows 0 for all four.

Copy puts the result on your clipboard and shows "Copied" for a moment. Download .txt saves the result as a UTF-8 text file. Copy and Download are off while the box is empty.

## Online text case converter: privacy

This online text case converter runs in your browser. The text you type is changed on your device. Nothing is uploaded or saved.

There is no account, no human check and no daily limit. The tool is free and has no API.

## Questions

### How do I change lower case to upper case?

Press the UPPER CASE button, and every letter in your text becomes a capital. The result appears in the "Result:" box as you type.

### How do I convert text to lowercase?

Press the lower case button. Every letter becomes small, so "Hello World" gives "hello world".

### What is the difference between sentence case and capitalize each word?

Sentence case capitalizes only the start of sentences and lines, and makes the rest lower case. Capitalize Each Word puts a capital on the first letter of every word.

### Why does ß become SS in upper case?

The standard case conversion in your browser turns ß into SS, so "straße" gives "STRASSE". The capital ẞ exists, but the tool does not use it.

### Why does the Turkish i need a language rule?

Turkish has a dotted İ and a dotless ı, so the letters do not pair up the way they do with the Default rules. Choose Turkish in the Language rules drop-down to get "İSTANBUL" from "istanbul".

### Can I use this to capitalize a title?

Capitalize Each Word puts a capital on every word, including small words like of and the. For title rules, use the Title Case Converter page on this site.

### Is the text I type uploaded?

No. The text is changed in your browser, and nothing is uploaded or saved.

### Is there a limit to the text length?

The box holds up to 200,000 characters.

### Can I download the result?

Yes. Download .txt saves the result as a plain UTF-8 text file. The file name matches the case you chose, such as upper-case.txt.

### Is the case converter free?

Yes. The tool is free, has no account, and has no daily limit.

## Related

- [Title Case Converter](https://aiipworld.com/tools/title-case-converter/index.md)

Page: https://aiipworld.com/tools/case-converter/