Sentence Case Converter

Sentence case follows these rules:

1. Capitalize the first word of every sentence, heading, or title.
2. Capitalize proper nouns such as names of people (Marie Curie), places (New York), organizations (NASA), and specific things (the Internet).
3. Capitalize the first word after sentence-ending punctuation (periods, exclamation marks, question marks).
4. Keep everything else lowercase, including adjectives, verbs, and common nouns that are not proper nouns.

For example: "The team traveled to Berlin for the annual conference." Here, only "The" (first word) and "Berlin" (proper noun) are capitalized.

Here are several examples showing text converted to sentence case:

• Original: "HOW TO WRITE BETTER EMAILS" → Sentence case: "How to write better emails"
• Original: "The CEO Of Apple Announced New Products" → Sentence case: "The CEO of Apple announced new products"
• Original: "understanding css grid and flexbox layouts" → Sentence case: "Understanding CSS grid and flexbox layouts"

Notice that proper nouns (Apple), acronyms (CEO, CSS), and the first word of each sentence stay capitalized, while all other words are lowercase.

Several major style guides and organizations recommend sentence case:

• APA Style requires sentence case for titles in reference lists and bibliographies.
• AP Stylebook uses sentence case for headlines in news articles.
• BBC News Style Guide uses sentence case for all headlines.
• Microsoft Writing Style Guide recommends sentence case for UI labels, headings, and titles.
• Google Developer Documentation Style Guide uses sentence case for headings and titles.

Many modern websites and apps also prefer sentence case because it reads naturally and feels less formal than title case.

Sentence case: Only the first word and proper nouns are capitalized. Example: "How to improve your website's search performance"

Title case: Most major words are capitalized. Example: "How to Improve Your Website's Search Performance"

Sentence case creates a conversational, approachable tone and is common in blog content, social media, and email marketing. Title case adds formality and is used in academic papers, traditional journalism, and book titles. Choose based on your brand voice and the style guide you follow.

Sentence case capitalizes only the first word and proper nouns: "The report was published in March."

Upper case capitalizes every letter: "THE REPORT WAS PUBLISHED IN MARCH."

Upper case is used for acronyms (NASA, HTML), short labels, or emphasis. Sentence case is the standard for readable body text and most headings. In general, avoid writing long passages in all caps because it reduces readability.

Watch for these frequent errors when applying sentence case:

• Capitalizing after colons: "Remember this: Consistency is everything" should be "Remember this: consistency is everything" (unless the style guide says otherwise).
• Lowercasing brand names: Always preserve official capitalization. iPhone, eBay, and PayPal stay as-is regardless of sentence position.
• Breaking acronyms: NASA, BBC, and HTML keep their standard capitalization in sentence case.
• Forgetting proper nouns: Names of people, places, and specific things always get capitals: "The workshop is in Manchester next Tuesday."

The converter recognizes approximately 3,000 proper nouns and abbreviations. After applying standard sentence case rules, it corrects words like NASA, iPhone, JavaScript, PostgreSQL, and place names like New York and Washington to their proper casing. This means most well-known acronyms, brand names, countries, cities, and technical terms are preserved automatically.

The dictionary may not cover every proper noun, especially uncommon personal names or niche terms. If a word is not in the built-in list, it will follow the default sentence case rules (lowercase unless it starts a sentence). You can manually adjust any remaining words after conversion.

Lowercase converts every letter to its lowercase form with no exceptions. Sentence case is more selective: it capitalizes the first letter of each sentence while lowercasing the rest. The result reads like standard written English. For example, "THE QUICK BROWN FOX" becomes "the quick brown fox" in lowercase, but "The quick brown fox" in sentence case. Use lowercase when you need uniformly small letters (CSS class names, URL slugs, data normalization). Use sentence case when the text needs to be human-readable and follow normal writing conventions.