Sentence Case Converter
Use the CaseSwitch Sentence Case Converter to turn ALL CAPS notes, OCR dumps, and mixed drafts into readable prose. Paste the text, review the live result, and copy it. Processing stays in this browser — nothing is uploaded.
Written by the CaseSwitch editorial team. We maintain these tools in the browser so drafts, keys, and images stay on your device.
Last reviewed: 30 August 2026
Processed locally in your browser. Nothing is sent to a server.
Paste or type text to convert. Output stays empty until there is input.
Character count: 0 · Word count: 0 · Line count: 0
Examples
Mixed casing after Caps Lock
Input
HELLO world. this IS a TEST!
Output
Hello world. This is a test!
Question mark starts the next sentence
Input
wait—what happened? nobody knows.
Output
Wait—what happened? Nobody knows.
Several lines
Input
first line. second LINE starts here.
Output
First line. Second line starts here.
Numbers stay numbers
Input
42 bottles. 3 remain.
Output
42 bottles. 3 remain.
Acronyms are not preserved
Input
WHAT ABOUT ACRONYMS LIKE HTML AND NASA?
Output
What about acronyms like html and nasa?
URL letters are lowercased
Input
https://Example.COM/Path
Output
Https://example.com/path
How to use
- Paste the paragraph, email, or notes into the input panel. Multiple sentences and line breaks are fine.
- Check names, brands, and acronyms in the output. The converter will not restore those for you.
- Copy the result, or download it if you want a file.
What this tool is for
Sentence case is the capitalization of ordinary English prose: the first letter of each sentence is a capital, and the rest of the sentence is lowercase except where a name, place, or acronym still needs its own capitals. That is how emails, articles, support replies, and most UI sentences are written. This page is for restoring that pattern after Caps Lock, a shouty export, or a paste that flattened everything to one case.
How it works
The converter lowercases the whole string first, then capitalizes the first letter it finds at the start of the text and the first letter after a period, question mark, or exclamation mark followed by space. It does not consult a dictionary of proper nouns, so “paris” stays “paris” unless you fix it. Numbers, emoji, and punctuation that are not those three sentence markers are left as they are.
When to use it
Use it on emails typed with Caps Lock, meeting notes from a phone, support tickets, OCR from a PDF, and blog drafts that went through an uppercase filter. It is the right tool when the destination is a paragraph, a message, or a UI sentence — not a headline. Product copy, error messages, and documentation body text almost always belong in sentence case because it is easier to scan than a wall of capitals.
When not to use it
Do not run article titles, navigation labels, or legal headings through sentence case if your house style wants title case. Do not expect it to restore brand spelling (iPhone, McDonald’s) or all-caps acronyms (NASA, HTML). Those need a human pass after the mechanical lowercase. Abbreviations such as “Dr.” can look like the end of a sentence and capitalize the next word by accident.
How it compares to related tools
Title case capitalizes major words in a heading and is the usual choice for blog titles and H1s. Capitalized case capitalizes every word, including “And” and “The,” which is heavier than most publishing styles. Upper case shouts the whole string. Sentence case is the only one of these meant for paragraphs and email bodies. If Caps Lock inverted letters instead of uppercasing them (hELLO), run Inverse Case first, then this converter. Longer comparison: Sentence Case vs Title Case.
Common mistakes
Pasting a heading and wondering why “The Quick Brown Fox” became “The quick brown fox” — that is correct sentence-case behavior. Converting a list of product names and losing intended capitals. Treating “Dr. Smith” as two sentences (the period after Dr. can capitalize “Smith,” which happens to be right, while “dr.” itself is lowercased). Converting live URLs or emails: letters inside them are lowercased, which can break case-sensitive paths.
Sentence case in UI and accessibility
Most modern product teams write buttons and menu items in sentence case (“Save changes,” “Delete account”) because it matches how people read body text and is less shouty than capitalizing every word. Screen readers also treat a sentence-case string as language rather than a string of independent title words. If your design system already specifies sentence case for UI, convert the copy here, then restore the few product names that need internal capitals.
Abbreviations, URLs, and empty input
A period, question mark, or exclamation mark plus a following space is treated as a sentence boundary. That is why “Dr. Smith” can split: “dr.” is lowercased and “Smith” is capitalized as if a new sentence began. Em dashes, commas, and colons do not start a new sentence. URLs and email addresses are lowercased letter by letter — convert labels, not live links. Empty input produces empty output; the editor stays blank until you paste something.
Frequently asked questions
What is sentence case?+
Sentence case capitalizes the first letter of each sentence and leaves the rest lowercase, except where you still need proper nouns. Example: “The meeting is at noon. Please bring notes.”
Does this converter capitalize names automatically?+
No. It follows punctuation, not a name dictionary. After conversion, scan for people, places, brands, and acronyms and restore their usual capitals.
What counts as the start of a sentence?+
The first letter of the text, and the first letter after a period, question mark, or exclamation mark plus following space. “Dr.” and similar abbreviations can fool that rule — check those lines.
Should I use sentence case for blog titles?+
Usually no. English blog titles are typically title case or a house style. Use the Title Case Converter for headings and this tool for the article body. Some newsrooms prefer sentence-style headlines; follow that guide if you have one.
Can I convert multiple paragraphs at once?+
Yes. Paste as many paragraphs as you need. Each sentence after “.”, “?”, or “!” plus space is capitalized. Very large pastes may run slower in the browser (there is a size cap so the tab stays responsive).
Is my text uploaded?+
No. Conversion runs in this browser. You can disconnect after the page loads and still convert.
Does CaseSwitch upload this text?+
No. Conversion, cleaning, and counting for this page run in your browser. Drafts are not sent to CaseSwitch for processing.
Related guides
Read our original articles on this topic.
Guides
Sentence Case vs Title Case: Which Should You Use?
Same words, different capitalization. A practical guide to picking sentence case or title case for emails, headings, buttons, and social posts.
Tips
How to Fix Accidental Caps Lock Text
Typed with Caps Lock on? Paste into a case converter — sentence case for prose, lowercase for slugs. No retyping required.
Guides
What Is Title Case? When to Use It (and When Not To)
Title case capitalizes major words in headings. Learn how it differs from sentence case and capitalized case, with examples for blogs, emails, and UI labels.
Related tools
Title Case Converter
Format blog post titles, slide decks, README headings, newsletter subject lines that your brand treats as titles, documentation section names, and book or article titles in English. It is faster than retouching twenty headings by hand after a draft in sentence case. Convert the heading list; leave the article body in sentence case.
Upper Case Converter
Warning banners, warehouse and packing labels, form section names that a design system specifies in caps, crossword-style puzzles, matching a legacy field that stores values in uppercase, and preparing a short line that must be visible at a distance. Keep the string short. A five-word label in caps can work; a paragraph will not.
Lower Case Converter
Preparing tags, normalizing CSV columns, turning a headline into input for a slug generator, lowercasing identifiers before a further snake_case or kebab-case conversion, and calming an accidental Caps Lock paragraph when you do not need sentence capitals yet. Also useful when two systems disagree about case and you need a single canonical form for comparison.
Inverse Case Converter
Rescuing a paragraph typed with Caps Lock and Shift, reversing alternating-case jokes, checking how a UI looks with inverted labels in a fixture, and fixing a short paste before you apply sentence case for readable prose.
Capitalized Case Converter
Button and menu labels in a design system that specifies Start Case (“Save Changes”), spreadsheet column headers, form legends, short display names, and feature lists copied in lowercase. It is a fast way to make every word look intentional when title case would leave “of” and “the” small and you do not want that.