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TextLabFree sentence case converter
Sentence case that knows where a sentence ends
This converter drops the whole text to small letters and then raises a single capital wherever a sentence begins. The tool is free, no signup stands in the way, and there is no cap on how much you paste. The capital is the easy half — the work is in the full stops, and this one knows that Dr. and e.g. do not end a sentence, that 3.14 is a number rather than two, and that the she in “Stop!” she said stays small. It keeps the pronoun I and every word you capitalised mid-sentence, and it changes tactics automatically when the whole paste arrives in capitals.
- 100% free
- No signup
- Knows Dr. and 3.14
- Keeps I and your names
- Rebuilds ALL-CAPS text
Separate them with commas. They come out spelled exactly as you type them here.
On by itself for an all-capitals paste. Turn it on by hand for text where the capitals were sprinkled at random.
How to put text into sentence case
Three steps, and the third is worth thirty seconds on anything you are about to publish.
Drop in the text whose capitals are wrong
A meeting transcript, a product feed that arrived in capitals, an email someone typed in a hurry, a notice set in caps by a system nobody maintains any more. Hit the paste shortcut from wherever you are on the page: ⌘V on macOS, Ctrl+V on Windows or Linux. A banner appears if the whole paste is in capitals, because that changes how the tool has to work.
Tell it the names it has no way of knowing
In ordinary mixed-case text you can usually skip this: a word you capitalised in the middle of a sentence is treated as your own evidence that it is a name, and left alone. In an all-capitals paste that evidence is gone, so type the names into the box — Priya, Manchester, Novartis — separated by commas, and they come back spelled exactly as you typed them there.
Check both panels, then copy
The left panel lists the opening words of every sentence the tool found, in order, which is the fastest way to spot a full stop it read wrongly — a sentence that starts mid-thought means a boundary landed in the wrong place. The right panel names every capital it kept and why it kept it. Copy the tidied text takes the result to your clipboard as plain text.
Technical specifications
| What it produces | One capital at the start of every sentence, everything else in small letters except the words it can justify keeping |
|---|---|
| Where a sentence starts | After a full stop, question mark or exclamation mark followed by whitespace or the end of a line, and at the first word of every non-empty line |
| What is not a boundary | 62 abbreviations (Dr., e.g., Inc., Vol., Sept.), any single-letter initial, a full stop between two digits, a full stop with no space after it, and any run of two or more full stops |
| Quoted dialogue | A terminator tucked inside a closing quote only ends the sentence when the next word already carries a capital, so "Stop!" she said keeps its lowercase she |
| Capitals that survive | The pronoun I and its four contractions, runs of two or more capitals, any word you capitalised mid-sentence, 40 built-in weekday, month, language and place names, and your own comma-separated list |
| All-capitals input | Detected automatically and handled differently: mid-sentence capitals stop counting as evidence, and names come from the built-in list and your box instead |
| What it shows you | The opening words of every sentence it found, numbered in order, beside a list of each kept capital with the reason it was kept |
| Speed, limit and cost | No length cap; a 6,000-word transcript is recased in about 2 ms. Free, no account, and the text never leaves the browser tab |
Frequently asked questions
How does it know that Dr. Smith is not the end of a sentence?
It checks the word in front of the full stop against a list of 62 abbreviations and treats any single letter as an initial. Dr., Mrs., Prof., St., etc., e.g., i.e., Inc., Ltd., Vol., Fig. and the three-letter months and weekdays are all on the list, and J. R. R. Tolkien passes through as one name rather than four sentences. Words that are also ordinary English — no, min, max — are deliberately left off, because putting them on would swallow the full stop in a sentence that really does end with the answer is no.
Will it lowercase the names in my text?
Not in ordinary mixed-case text, because a capital in the middle of a sentence is taken as your own evidence that the word is a name and is left exactly as you typed it. That is the only honest rule available without a dictionary of every person, company and street on earth, and it means London, Novartis and O'Brien survive untouched. An all-capitals paste has no such evidence in it, so the tool falls back on a built-in list of 40 weekdays, months, languages and places, plus whatever you add to the box.
What happens to dialogue like "Stop!" she said?
The she stays lowercase, which is what a copy editor wants. An exclamation mark or question mark that sits inside a closing quotation mark counts as an ending only when the next word already carries a capital, because in English the dialogue tag after a quotation carries on the same sentence. The rule cannot survive an all-capitals paste, where every word looks capitalised, so quoted dialogue in shouted text is the one place you should read the result before trusting it.
Does a decimal point or a web address split a sentence?
No — a full stop with a digit on both sides is never a boundary, so 3.14, 1.5 million and version 2.0 stay whole. A full stop with no space after it is not a boundary either, which keeps example.com and filenames intact. The boundary rule is deliberately strict: a full stop, question mark or exclamation mark has to be followed by whitespace or the end of the line before anything happens.
Does an ellipsis start a new sentence?
No, two or more full stops in a row are read as an ellipsis and left alone, so he paused... then left keeps its small t. Ellipses inside a sentence are far commoner in the kind of text people paste here than ellipses closing one. If your ellipsis really did end a sentence, the following word almost certainly already has its capital, and mid-sentence capitals are protected, so it will survive anyway.
Why did a line in the middle of my paragraph get a capital?
Because every non-empty line is treated as the start of a sentence, and your paragraph is hard-wrapped. Text copied out of a PDF, or out of an older mail program, usually keeps a break where the printed line stopped rather than where the paragraph did, and nothing in the file marks which breaks were deliberate. Run the text through the remove line breaks tool first to rejoin the paragraphs, then bring it back here — the two together fix a PDF paste completely.
How do I fix a whole document that was written in capitals?
Paste it and let the banner appear: the tool notices that nothing in the text is lowercase and changes strategy by itself, because in an all-capitals paste the usual clues are gone. Every word comes down, each sentence opening comes back up, the pronoun I is restored, and names come from the built-in list plus your own. Expect to fix a handful of things by hand afterwards, since an acronym such as NHS looks no different from any other shouted word and comes back as Nhs.
Finding the end of a sentence is the entire problem
Putting a capital on the first letter of a sentence is trivial. Working out which letter that is, is not, because the full stop in English holds down four jobs at once and only one of them ends anything. Consider Dr. J. R. R. Tolkien published 3.5 million words. — six full stops, and only the last of them closes a sentence. Add web addresses, version numbers, ellipses and the abbreviations that infest business and academic prose, and a converter that treats every full stop as a boundary will scatter capitals through the middle of your paragraphs. This one checks the word in front of the stop against a list of 62 abbreviations, treats any lone letter as an initial, refuses to split between two digits, and insists on whitespace afterwards before it does anything at all.
The second problem is knowing what to leave alone, and here the honest answer is that a program cannot tell polish from Polish without understanding the sentence. What it can do is trust you. A capital you typed in the middle of a line is evidence — nobody capitalises a word there by accident — so those words are kept exactly as written, along with the pronoun I, its four contractions and any run of two or more capitals. That evidence vanishes the moment the whole text arrives in capitals, which is why an all-caps paste is treated as a different problem: the clues are gone, so names have to come from a built-in list of 40 and from the box you fill in yourself. Expect an all-caps job to need a few manual corrections afterwards; an acronym in a shouted line is genuinely indistinguishable from a shouted word.
The line break is the last trap, and it catches almost everyone at least once. Every non-empty line here begins a new sentence, which is right for a list, a set of subtitles or a transcript with one speaker turn per line, and wrong for a paragraph that was hard-wrapped when it was copied out of a PDF. Rejoin those paragraphs with the remove line breaks tool before you recase them and the two operations together will clean up a PDF paste properly. To check afterwards that the tool split the text where you would have, the sentence counter shows the length of every sentence it found; and if the capitals are merely part of what is wrong with the paste, the case converter holds the other six ways of recasing a line, including the plain lowercase pass for text that has no sentences in it at all.
Transcripts, notices and other people's words
The text you paste here is often somebody else's: an interview transcript, a legal notice, a support thread, a set of medical instructions written in capitals by a system from 1998. None of it is uploaded. The sentence detection, the capitals and both panels are computed by JavaScript inside this tab, the names you type in the protect box are not stored, and closing the page destroys every trace of what you were working on.