The Fundamental Difference
Title Case capitalizes the first letter of most words: The Quick Brown Fox Jumps Over the Lazy Dog.
Sentence case capitalizes only the first word of a sentence and proper nouns: The quick brown fox jumps over the lazy dog.
Neither is universally "correct" — the right choice depends on context, medium, and style guide. But mixing them inconsistently is always wrong.
When to Use Title Case
Article Headlines and Blog Post Titles
Most English-language publications use title case for their main headlines. The major style guides — AP, Chicago, MLA — all have slightly different rules about which words to capitalize (prepositions, articles, conjunctions vary), but most use title case as the default for headings.
Book and Film Titles
To Kill a Mockingbird. The Shawshank Redemption. Harry Potter and the Chamber of Secrets. Title case is the convention for named creative works.
Software and UI Elements
Most software user interfaces use title case for menu items, button labels, and navigation elements: Save As, Export File, Edit Profile. This creates clear visual hierarchy and matches user expectations.
Company Names and Product Names
When writing about products or companies, follow the entity's own capitalization convention. Apple uses "iPhone", not "Iphone" or "IPHONE." Microsoft uses "Microsoft Word", not "Microsoft word."
When to Use Sentence Case
Email Subject Lines
Most email marketing best practices recommend sentence case for subject lines. Research from Mailchimp and HubSpot consistently shows sentence case performs better in A/B tests — it reads more like a personal message and less like an advertisement.
Compare: ANNOUNCING OUR SPRING SALE vs. Our spring collection is here — 30% off today. The sentence case version feels more human.
Social Media Posts
Conversational content on social media uses sentence case almost universally. All-caps reads as shouting; Title Case feels stiff. Write the way you'd speak in a professional but friendly conversation.
Body Copy and Articles
All continuous prose — articles, blog posts, documentation — uses sentence case. Only headings within the content may use title case (depending on the publication's style guide).
Subheadings (Often)
This is where it gets nuanced. Some publications (like Google's developer documentation and many tech companies) use sentence case for all headings, including H2s and H3s. Others use title case for H1 and H2 but sentence case for H3 and below. The most important thing is consistency within a single piece.
Style Guide Quick Reference
- AP Style: Title case for headlines; capitalize main words, lowercase articles/short prepositions.
- Chicago Manual of Style: Title case for titles and headings; capitalize all words except articles, prepositions under 5 letters, and coordinating conjunctions.
- APA Style: Sentence case for article titles in reference lists; title case for journal names.
- Google / Material Design: Sentence case for UI elements and headings.
- Microsoft Writing Style Guide: Sentence case for everything — headings, titles, UI elements.
The SEO Angle
From a pure search ranking perspective, capitalization doesn't affect rankings. Google understands both "best coffee shops in London" and "Best Coffee Shops in London" as the same query. However, capitalization affects click-through rates. Title-cased headlines in SERPs tend to stand out and signal that the result is a structured, authoritative resource. Test both in your content and watch your CTR data.
How to Convert Case Instantly
Manually re-capitalizing a 1,500-word document is painful — one wrong click and you're hunting through text for stray capitals. A case converter tool can flip an entire document from title case to sentence case (or any other format) in under a second, with no risk of missing a word.