Which words does Title case leave lowercase?

Short function words: a, an, and, as, at, but, by, for, in, nor, of, on, or, per, the, to, vs and via. The first word of the text is always capitalised, whatever it is.

Does it keep my brand names and acronyms?

No, and this is the important limitation. A case converter does not know that iPhone, macOS or PDF are meant to be written that way, so it will turn them into Iphone, Macos and Pdf. Convert only the parts of a text that are plain prose.

What is the difference between Sentence case and Title case?

Sentence case capitalises the first word and the first word after a full stop, a question mark or an exclamation mark, and leaves the rest lower. Title case capitalises every word except the short function words.

Is my text saved anywhere?

No. Everything runs in your browser and the tool keeps no copy of what you paste.

How-to guides

How to Change the Case of Text (and Why It Ruins Brand Names)

Case conversion is a blunt instrument: it knows about capitalisation and nothing else. Here is what each style does, and the words it will destroy.

Zahid SheerazOctober 22, 20264 min read

There are four ways to change the case of a block of text, and they are not four flavours of the same thing. Each one makes a different set of decisions about which words deserve a capital letter - and each one will happily destroy something you wanted to keep.

What each style actually does

UPPER makes every letter capital. That is the whole of it: no exceptions, no small words left alone.

lower is the same in reverse - every letter lower case.

Sentence case lower-cases everything first, then puts a capital on the first word of the text and on the first word after a full stop, a question mark or an exclamation mark. So:

THIS IS A SENTENCE. AND THIS IS ANOTHER ONE! IS IT?

becomes

This is a sentence. And this is another one! Is it?

That is the style for body text, for UI labels, and for rescuing a paragraph someone sent you in caps.

Title case lower-cases everything first, then capitalises every word - except the short function words, which stay lower case. The list is: a, an, and, as, at, but, by, for, in, nor, of, on, or, per, the, to, vs, via.

So a journey to the end of the night comes out as A Journey to the End of the Night - the first word is always capitalised whatever it is, and the small words in the middle stay down.

The rule that trips people up

Title case here works word by word, not sentence by sentence.

Look at what happens to a small word that starts a sentence:

this is a sentence. and this is another one! is it?

becomes

This Is a Sentence. and This Is Another One! Is It?

The "and" after the full stop stays lowercase, because "and" is a small word and the rule looks at each word on its own. The "This" after the full stop is capitalised, because "this" is not on the small-word list.

It looks wrong, because a capitalised word after a full stop is what a reader expects. If the small words matter to you, fix them by hand afterwards - there are usually two or three, and they are always the same ones.

The limitation that matters most

Here is the thing a case converter cannot do, no matter how good it is:

It does not know which words are supposed to be capitalised.

Take this line:

iPhone and macOS and PDF

Every one of those is capitalised on purpose. The converter sees a list of words, applies the rule, and gives you:

Iphone and Macos and Pdf

Which is wrong in three places, and there is no setting that fixes it. The tool has no dictionary of product names, no list of acronyms, and no idea that "PDF" is a format rather than a word.

So the rule is simple: convert the prose, and leave the names alone.

A heading like how to merge pdf files → How to Merge PDF Files ✅ (the "pdf" gets capitalised by the title rule, which is what you wanted anyway)
A paragraph mentioning iPhone and macOS → do not run the converter over it ❌

If a text mixes both - a heading and a paragraph about products - convert the heading and leave the paragraph alone. The converter is instant; so is your own cursor.

When to use which

Your text	Use	Because
A heading or a title	Title case	The small words read better down
A label, a button, a menu item	Sentence case	It is what UI convention asks for
A paragraph someone sent in caps	Sentence case	It turns shouting into sentences
A column header in a spreadsheet	Sentence case	Short, scannable, consistent
A file name or a slug	lower	No surprises with case-sensitive systems
A product name, an acronym, code	none of them	They will be destroyed
A legal document or a contract	none of them	Capitalisation can carry meaning there

That last row deserves a word. In some kinds of writing, the capitalisation is the meaning - "the company Amazon" versus "amazon", or an acronym that is defined by its case. That is rare, but when it applies, a converter is the wrong tool.

A practical workflow

Copy the prose only, not the whole document.
Run the style you need - the result appears as you type.
Paste it back and fix the two or three words that were names.
Read the first line and the last line. They are the ones with the most capitalisation decisions on them, and the ones a reader notices first.

Step 3 is not optional if the text contains any proper noun, and step 4 takes ten seconds.

A short checklist

Title case leaves small words down: a, an, and, as, at, but, by, for, in, nor, of, on, or, per, the, to, vs, via.
The first word is always capitalised, small word or not.
Title case works word by word, so a small word starting a sentence stays lower.
Brand names and acronyms will be broken - convert the prose, not the names.
Sentence case is for body text and UI labels; Title case is for headings.
UPPER and lower are lossless in one direction only - you cannot get the capitals back.
It runs in your browser and keeps no copy of what you paste.