Sentence Case Converter — Fix Text Capitalization Instantly
This sentence case converter fixes ALL-CAPS paragraphs, random Title Case text, and mixed-case content in one click — capitalizing only the first letter of each sentence and leaving everything else lowercase. Google Material Design, Microsoft Style Guide, and Apple's Human Interface Guidelines all recommend sentence case for UI labels, buttons, and app headings. APA 7th Edition and MLA 9th Edition both require sentence case for titles in reference lists. Paste any text, get clean sentence case output instantly — no signup, no character limit.
What is Sentence case?
The sentence case converter capitalizes only the first letter of each sentence, leaving everything else lowercase — paste ALL CAPS or Title Case text and get natural, readable output in one click. Google, Microsoft, and Apple all use sentence case for UI labels, meta descriptions, and product copy. Proper nouns will need a quick manual review after conversion.
HELLO WORLD. HOW ARE YOU?→Hello world. How are you?Key Features
Multi-Sentence Detection
Detects sentence boundaries at every period ( . ), exclamation mark ( ! ), and question mark ( ? ) — capitalizing the first letter after each one automatically. Handles multi-paragraph input in a single pass.
Fixes ALL CAPS & Title Case in One Step
Paste text from a PDF export, spreadsheet header, or old CMS and get clean, natural sentence case output instantly. Works equally well on ALL CAPS, Title Case, or any mix of the two.
Safe for Email Copy, Support Scripts, and CMS Drafts
Your email copy, product descriptions, and support scripts never leave your device. Nothing is transmitted to any server — safe for confidential content.
APA 7th and MLA 9th Reference List Ready
Both APA 7th Edition and MLA 9th Edition require sentence case for article and book titles in reference lists. Paste your bibliography titles, convert, then manually re-capitalize proper nouns — the fastest way to format academic citations correctly.
Before & After: Sentence case Examples
Real input → output pairs showing exactly how the converter behaves
| Input | Sentence case Output |
|---|---|
THE QUICK BROWN FOX JUMPS. | The quick brown fox jumps. |
hello world. how are you? | Hello world. How are you? |
Title Case Heading Here | Title case heading here |
i love javascript and python. | I love javascript and python. |
what is sentence case? it is easy! | What is sentence case? It is easy! |
When to Use Sentence case
Use Sentence case for any running text: emails, blog body paragraphs, UI tooltips, descriptions, status messages, and social media posts. It reads most naturally because it matches how we read books and articles.
Do not use Sentence case for titles, headings, or navigation items where Title Case is expected by convention, or for acronyms and proper nouns that require their own capitalization rules.
Sentence case vs Other Formats
| Format | Example | Best For |
|---|---|---|
| Sentence case | The quick brown fox | UI labels, buttons, app headings, meta descriptions, social captions, email body, APA/MLA reference titles |
| Title Case | The Quick Brown Fox | Blog headlines, YouTube titles, book chapters, product names, article headlines, email subject lines |
| UPPERCASE | THE QUICK BROWN FOX | SQL keywords, environment variables, programming constants, legal warranty clauses |
| lowercase | the quick brown fox | URL slugs, CSS class names, code variable prep before snake_case or kebab-case conversion |
Who Should Use This Tool?
Fix ALL-CAPS pasted copy and normalize email body text to sentence case for a professional, readable tone before sending campaigns via Mailchimp, Klaviyo, or HubSpot.
Convert caption drafts from title case to sentence case — the preferred style for Instagram, Facebook, and LinkedIn post bodies according to each platform's own content guidelines.
Clean up Zendesk ticket responses, Intercom knowledge base articles, and chatbot scripts written or imported with inconsistent capitalization — matching the sentence case standard used by Notion, Linear, and Figma.
Industry Standard
Sentence case is the default capitalization standard recommended by the Google Material Design and Microsoft Fluent Design guidelines for UI text — labels, tooltips, and descriptions should use sentence case, not title case.
Sentence case Rules: How It Works
- →First letter of the entire input — no exceptions
- →First letter after a sentence-ending period ( . )
- →First letter after an exclamation mark ( ! )
- →First letter after a question mark ( ? )
- ×All letters mid-sentence — including proper nouns like "london" or "amazon"
- ×Brand names and product names — "iphone", "javascript", "chatgpt"
- ×Abbreviations mid-sentence — "nasa", "html", "api"
How to Use This Sentence case Converter
- Paste or type your text into the Input Text box on the left.
- The output is converted to Sentence case instantly on the right.
- Click Copy to copy the result to your clipboard.
- Use Clear to reset and convert new text.
Key Use Cases
- →Fix ALL-CAPS text pasted from PDFs, spreadsheet headers, or legacy CMS exports into WordPress, Ghost, Webflow, or Notion — restoring natural readability in one step.
- →Normalize Google Ads and Meta Ads body copy drafted in Title Case or ALL CAPS to sentence case — Google's own ad writing guidelines recommend sentence case for ad descriptions.
- →Prepare APA 7th Edition and MLA 9th Edition reference list titles — both style guides require sentence case for book and article titles in reference lists (capitalize only the first word and proper nouns).
- →Convert title-cased social media captions to sentence case for Instagram, Facebook, and LinkedIn — where sentence case reads more naturally and matches platform conventions.
- →Clean up chatbot scripts, Zendesk help center articles, and Intercom messages that were imported or written with inconsistent ALL CAPS or Title Case formatting.
Sentence case in Programming Languages
str.charAt(0).toUpperCase() + str.slice(1).toLowerCase()str.capitalize()ucfirst(strtolower($str))str.capitalizeThis Converter vs Manual Methods
| Method | Limitation |
|---|---|
| Shift+F3 in Microsoft Word | Cycles through cases but does not detect sentence boundaries — does not apply proper sentence case to multi-sentence text |
| Format → Capitalization in Google Docs | Only capitalizes the very first letter of the selection — does not handle multiple sentences |
| Find & Replace with regex | Requires regex knowledge; fragile for multi-sentence text; breaks on abbreviations like "Dr." or "U.S.A." |
| Grammarly capitalization suggestion | Suggestion-only; requires paid subscription; not a bulk converter |
| This converter | None — free, unlimited, browser-based, multi-sentence aware |
Common Mistakes & Pro Tips
- !Publishing proper nouns in lowercase without reviewing — the converter cannot detect names, places, or brands. Words like "New York", "Amazon", "iPhone", "JavaScript", and "ChatGPT" will appear lowercase mid-sentence. Always proofread output for proper nouns before publishing, or run the result through Grammarly to catch capitalization issues.
- !Using sentence case for H1 and H2 page headings when your brand guide requires title case — Google Material Design and Microsoft Style Guide recommend sentence case for UI labels, but AP Style, Chicago Manual, and most editorial brands use title case for article headlines and page headings. Check your specific style guide before applying sentence case to headings.
- !Confusing sentence case with lowercase — sentence case preserves the capital at the start of each sentence ("Hello world. How are you?"); lowercase removes every capital ("hello world. how are you?"). For body copy and UI labels, sentence case is almost always the right choice; all-lowercase is a deliberate stylistic choice, not a default.
Frequently Asked Questions
Everything you need to know about Sentence case
Does sentence case capitalize proper nouns automatically?
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No — the converter applies a rule-based transformation and cannot identify proper nouns. It capitalizes the first letter after a sentence-ending punctuation mark and lowercases everything else. Words like "london", "javascript", or "amazon" will appear in lowercase mid-sentence. Manually re-capitalize proper nouns after conversion, or run the result through Grammarly to identify them.
How does the tool detect sentence boundaries?
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The converter looks for sentence-terminating characters — period (.), exclamation mark (!), and question mark (?) — followed by whitespace, then capitalizes the next alphabetic character. It also capitalizes the very first character of the input. Edge cases like "Dr. Smith", "U.S.A.", or "e.g." may falsely trigger a new-sentence capital since they contain periods — review those after conversion.
What is the difference between sentence case and lowercase?
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Lowercase converts every single letter to its small form, including the first letter of every sentence: "hello world. how are you?" Sentence case preserves the sentence-starting capital: "Hello world. How are you?" Sentence case is the natural writing style for prose, UI labels, and body copy. All-lowercase is a deliberate stylistic choice sometimes used in social media or branding but avoided in professional and editorial writing.
Should UI button labels use sentence case or title case?
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Google Material Design recommends sentence case for all UI elements — "Save changes", "Create new project". Microsoft Style Guide recommends sentence-style capitalization for most titles and headings. Apple's Human Interface Guidelines allow both but favor sentence case for modern iOS and macOS interfaces. Most modern SaaS products — Notion, Linear, Figma, Stripe, Slack — use sentence case for labels and title case only for top-level page headings.
Can I use sentence case for APA or MLA citations?
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Yes — APA 7th Edition requires sentence case for article and book titles in reference lists: capitalize only the first word, the first word after a colon or dash, and proper nouns. MLA 9th Edition applies the same rule for works cited entries. Both styles use title case for the paper's own headings and running heads. Journal, magazine, and newspaper names are exceptions — they always use title case regardless of style guide.
Why do Google, Microsoft, and Apple recommend sentence case for UI?
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Sue Factor, Google's first UX writer, explained that sentence case was chosen for Google's products because it is easier to explain consistently to designers and engineers than title case rules. Microsoft's style guide notes that sentence case is more readable and easier to localize. Research by John Saito (Medium: "Making a Case for Letter Case") found that sentence case feels friendlier and more conversational — better suited to the tone of modern digital products than the formal register of title case.
How do I convert to sentence case in Microsoft Word, Google Docs, and Notion?
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Microsoft Word: select text → Home tab → Font group → Change Case → Sentence case. This capitalizes the first letter of the selection only — not each sentence boundary. Google Docs: select text → Format → Text → Capitalization → lowercase (then manually capitalize sentence starters). Notion: no built-in sentence case option — paste your text into this converter and copy the result back. For multi-sentence text from any source, this converter is the fastest and most accurate option.