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Lowercase Converter

Undo Caps Lock or normalize text to lowercase, but keep the capitals you want: sentence starts, line starts or acronyms like NASA.

Processed locally in your browser

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What is Lowercase Converter?

Lowercase conversion replaces every capital letter with its small form. Besides the plain "everything lowercase" mode, this tool can leave the first letter of the text, of each line or of each sentence untouched, so a shouted paragraph becomes readable prose in one step. Acronyms of two or more capitals, such as NASA, USB or HTML5, can be kept as they are.

Lowercasing is language dependent. In Turkish and Azerbaijani the capital I becomes the dotless ı and İ becomes i, while the standard rule produces a plain i for both. Greek is handled too: a capital sigma at the end of a word becomes the final form ς. URLs, e-mail addresses and `code` spans are protected by default, because the path of a link is case-sensitive.

How does it work?

  1. Paste or type the text you want in lowercase.
  2. Choose whether to lowercase everything, or everything except the first letter of the text, each sentence or each line.
  3. Tick "keep acronyms" to preserve words such as NASA or USB, and switch to Turkish rules if needed.
  4. Leave URL and e-mail protection on to keep links intact, then copy the result.

Common use cases

  • Fixing a paragraph typed with Caps Lock while keeping the capital at the start of each sentence.
  • Normalizing e-mail lists, tags, usernames or keywords to lowercase before comparing or importing them.
  • Converting ALL-CAPS headlines to normal case without flattening acronyms such as NASA or FBI.
  • Preparing case-insensitive search keys, file names or CSS class names.

Examples

Try this input in the tool above:

Input
The NASA Team Met At 9 AM. They Checked The USB Logs!
VISIT HTTPS://EXAMPLE.COM/DOCS OR EMAIL INFO@EXAMPLE.COM. ISTANBUL: IRMAK
Output
The NASA team met at 9 AM. They checked the USB logs!
Visit HTTPS://EXAMPLE.COM/DOCS or email INFO@EXAMPLE.COM. Istanbul: irmak

Privacy

Lowercase Converter runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

Proper nouns cannot be recognized: lowercasing "PARIS" gives "paris", and you must recapitalize names by hand. Sentence detection is punctuation-based, so an abbreviation followed by a space counts as a sentence end.

Frequently asked questions

How do I keep the first letter of every sentence capitalized?

Choose "Everything except the first letter of each sentence". The first letter of each sentence stays as you typed it and every other letter becomes lowercase.

What does the acronym option keep?

Words made only of capitals and digits that contain at least two capital letters, such as NASA, USB or HTML5. A single capital such as "I" or "A" is treated as a normal letter. On a line typed entirely in capitals no acronym can be recognized, so that line is fully lowercased.

Why are URLs protected?

The host of a URL is case-insensitive but the path and query often are not, so lowercasing https://example.com/Docs could break the link. Untick the protection to convert everything.

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