Case Converter

What does a case converter do, and when do you need one?

A case converter changes the capitalization of text without retyping it: UPPERCASE, lowercase, sentence case or one of two title styles. Words, spaces and punctuation stay exactly where they are; only the letters switch between capital and small forms. This one offers six conversions, and each follows the language rules you pick at the top.

In my own work I reach for it in four situations:

• Supplier feeds: product names often arrive in capitals. I convert them to Title Case before they go into an online shop.
• CAPS LOCK accidents: tOGGLE cASE fixes a paragraph typed with the key left on in a single click.
• Page titles: I keep blog and page titles in one consistent style, then check their length with the word counter.
• Ad copy: headlines written in capitals go back to normal case before they reach an ad.

After converting a headline, paste it into the Google SERP preview to see how it will look in search results. For the page address, the slug generator lowercases letters and strips special characters on its own.

Why does a case converter need language rules?

Capitalization looks universal, but a few letters behave differently by language. Turkish, for example, has two letters where English has one: dotted i pairs with İ, and dotless ı pairs with I. Software that converts text without a language setting uses the English pairing. The Unicode SpecialCasing file keeps a separate section for Turkish and Azeri for exactly this reason.

In practice that produces three mistakes I see again and again:

• istanbul → ISTANBUL: with English rules the dot disappears. The Turkish spelling is İSTANBUL.
• IŞIK → işik: the dotless I turns into a dotted i. Correct Turkish is ışık.
• İZMİR → i̇zmir: lowered with English rules, İ becomes an i plus a separate combining dot. It barely shows on screen, yet a spreadsheet lookup will not treat it as izmir.

With Turkish rules selected, this tool uses the browser's tr-TR mapping, so all three come out right. If English or German rules are active and the text contains ı, İ, ş or ğ, the result badge turns amber and suggests switching. The reverse matters too: English rules are the right choice for an English brand name, because Turkish rules turn instagram into İNSTAGRAM. For mixed-language text, I convert each part separately.

Title Case or Capitalized Case: which one should your headlines use?

Capitalized Case is the simple rule: every word starts with a capital, including a, of and the. Title Case follows a style guide instead. Under English rules this tool uses the short word list from APA Style: articles, short conjunctions and prepositions of three letters or fewer stay lowercase, for example a, an, the, and, but, or, for, of, in, on, to, up and via. Words of four letters or more, such as with and from, start with a capital.

A few details the tool also handles for you:

• The first word always starts with a capital, even when it is a minor word.
• The first word after a colon starts with a capital too, so subtitles work.
• Hyphenated parts count as separate words: state-of-the-art becomes State-of-the-Art.
• Letters after an apostrophe stay lowercase, so don't becomes Don't rather than Don'T.

Other guides differ in the details. AP and Chicago, for instance, treat some prepositions differently, and no automatic tool can tell when up belongs to a phrasal verb such as Set Up. So I treat the output as a strong draft and check verbs and acronyms by hand. Consistency matters more than the style you choose; my guide to meta titles shows how I keep titles uniform across a site, and it is a standard part of our SEO consulting work.

When is sentence case the better choice?

Sentence case capitalizes only the first word of each sentence and each line, plus names you fix afterwards. It reads like normal speech, which is why I use it for buttons, menus, form labels and most body copy. Headlines in sentence case also look calmer next to each other in a blog list.

This tool starts a new sentence after a period, question mark, exclamation mark or ellipsis followed by a space, and at every line break. Two extras apply under English rules:

• The pronoun i becomes I, including i'm, i've, i'll and i'd.
• A number at the start of a sentence counts as the start, so the next word stays lowercase: 52 weeks a year, not 52 Weeks a year.

What the tool cannot know is which words are names or acronyms. After converting a paragraph typed in capitals, scan it for brands, cities and abbreviations like SEO, then restore them. Quotes and brackets at the start of a sentence are fine, however; the first letter inside them still becomes a capital.

If you write interface text, my UX writing guide covers where sentence case helps and where a label needs a different tone.

Can all-caps text cause problems in ads and social posts?

In Google Ads it can. The capitalization policy does not allow capitals that are not used correctly or for their intended purpose, and it shows three examples: FLOWERS, FlOwErS and F.L.O.W.E.R.S. It also lists exceptions:

• Common abbreviations such as ASAP.
• Coupon codes.
• Brand names, trademarks and product names with non-standard capitalization.

My routine for ad headlines is simple: convert to Title Case first, then restore acronyms and brand names by hand. A disapproved headline delays a campaign, so that check belongs before launch. It sits near the top of the ad copy checklist my team and I use in Google Ads management projects.

Organic social posts have no such review. Still, in my experience a long post in capitals tires readers; if something needs emphasis, one capitalized word does the job. Write the decision into your brand voice guidelines, for instance headlines in Title Case and body copy in sentence case.

Should you type capitals or use CSS text-transform?

When a design calls for capital letters in menus, buttons or headings, I keep the text in normal case and let CSS text-transform handle the look. The content stays clean in the database, and a redesign does not force you to retype hundreds of headings.

There is a catch for multilingual sites, though. According to MDN, text-transform applies language-specific mappings and reads the language from the lang attribute. If a Turkish page carries en as its language, the browser uppercases istanbul to ISTANBUL even in CSS. On German pages the same mechanism turns ß into SS. My checklist:

• Set lang to tr on Turkish pages, de on German pages and en on English ones.
• Use text-transform: uppercase when capitals are purely visual.
• Type acronyms and other always-capital terms directly.

I cover the accessibility side in my web accessibility guide, and the setup itself is part of every web design project my team and I deliver.

How do Word, Google Docs and Excel change case?

For short texts, office apps have their own options:

• Microsoft Word: the Change Case button on the Home tab offers Sentence case, lowercase, UPPERCASE, Capitalize Each Word and tOGGLE cASE. Shift+F3 cycles through lowercase, UPPERCASE and Capitalize Each Word.
• Google Docs: Format, then Text, then Capitalization offers lowercase, UPPERCASE and Title Case. Its Title Case capitalizes every word, which matches Capitalized Case here, and the menu has no sentence case option.
• Excel and Google Sheets: the UPPER, LOWER and PROPER functions convert the text in a cell.

Results with Turkish letters can depend on the app, its version and your language settings. Test a few words containing i, ı and İ before converting an important list. For bulk work I prefer this tool, because I choose the language rules explicitly and Title Case follows a named style.

Finally, do not confuse it with the fancy text generator. That tool swaps letters for decorative Unicode symbols; this one changes the letters themselves, so the result behaves like ordinary text anywhere you paste it.