“best practices for email subject lines” — Uppercase, Lowercase, Title Case and Sentence Case
Enter this string in the converter and these are the four outputs it returns. Nothing here is stored or guessed: the same regular expressions that run in your browser were run at build time, so the page and the tool agree character for character.
Where each form belongs
| Form | Result | Typical use |
|---|---|---|
| UPPERCASE | BEST PRACTICES FOR EMAIL SUBJECT LINES | Loud labels, ticker codes, shouting about a deadline |
| lowercase | best practices for email subject lines | Email addresses, URL slugs, file names |
| Title Case | Best Practices For Email Subject Lines | Headlines, button labels, menu items |
| Sentence case | Best practices for email subject lines | Body copy, descriptions, help text |
How the rules behave on this string
Every conversion starts from the same tidy-up: runs of spaces collapse to one and the ends are trimmed, while line breaks are preserved. Uppercase and lowercase then apply directly. Sentence case lowercases everything and re-capitalises the first letter after a full stop, question mark, exclamation mark or line break. Title case lowercases everything and re-capitalises the letter that follows the start of a line, a space, a quote, a bracket or an apostrophe.
Title Case here is a blanket rule: every word gets a capital, including the short ones. Writers who follow AP or Chicago style would leave of, the and and lowercase in a headline, so the Title Case line above is a starting point rather than a finished house style.
The four outputs differ only in where the capitals land, but the raw counts stay fixed: 33 letters, 12 vowels (36% of the letters), 5 non-letters and 6 words packed into 38 characters. Upper and lower case are exact inverses here — the 6 capitals that Title Case produces would become 33 under UPPERCASE and zero under lowercase. At position 37 among 76 strings in the reference, it averages 5.5 letters per word with “practices” the outlier at 9.
Similar strings
Frequently asked questions
What does each of the four results mean?
They are four separate passes over the same 38-character string. UPPERCASE and lowercase are the obvious ones. Title Case capitalises the first letter of every word, and Sentence case capitalises only the first letter of each sentence while forcing everything else down. The converter on the homepage builds them with the identical rules.
Which one should I paste into my document?
For a headline or a section title, Title Case is the conventional choice in English web copy, with the caveat that style guides keep short articles and prepositions lowercase. Sentence case reads more naturally in product interfaces and is what most design systems now ask for.
Converting a whole paragraph, a JSON key list or a batch of headlines? The CaseLabNow case converter takes free text up to several thousand characters, and the case reference library has a page for every string listed here.