Sentence case

The real case: text typed all in lowercase

Notes taken in a hurry on a phone, messages copied out of a chat, form fields filled in without looking at the keyboard: when that text has to go into a report, a description or an email, it needs standing back up. Here the capitals return where they belong, at the start of the text and after every full stop, exclamation mark, question mark or ellipsis, across every sentence at once.

How it recognizes a sentence

First the text is put entirely into lowercase, so a stretch accidentally typed in capitals gets evened out too; then a capital goes on the first letter of the text, on the first letter after an empty line and on the first letter after a full stop, an exclamation mark, a question mark or an ellipsis followed by a space or a line break. Doubled forms like «?!» and «...» count too, and quotes or brackets in between don't get in the way: «done. (more later)» becomes «Done. (More later)». Accented letters are treated like all the others and punctuation doesn't move. A list item gets a capital too: the first letter after «- », «* », «• », «1) » or «2. » at the start of a line.

The three things to check again

Any proper noun loses its capital, because no program can know that «brown» is a surname and not a colour: after the conversion they have to be put back by hand. The same goes for city names, company names and acronyms, which all end up lowercase.

Abbreviations are the delicate case. After the ones that never end a sentence, such as «e.g.», «i.e.», «vs.», «p.» or «fig.», the next word stays lowercase. After «etc.» and after titles like «Dr.» the capital goes on anyway, because a new sentence or a name almost always follows there: if the sentence carries on, fix it by hand. The original text helps, unless it's all in capitals: an acronym typed in capitals before the full stop, like «in CA.», ends the sentence, because it isn't the abbreviation «ca.» for circa, and the next word gets its capital; and a word that was capitalized after the abbreviation keeps its capital: «see e.g. Rome» becomes «See e.g. Rome». The pronoun «I», on the other hand, always gets its capital, «I'm» and «I'll» included. And a line starting after one that didn't end with a full stop does not get a capital, unless there's an empty line between the two: that's right for a text that wraps by itself, less so for a list without bullets where every line is its own entry. In that case Capitalize every word or a manual pass works better.

Nearby tools

For titles, where the capital goes on every word, the page is Capitalize every word. To move everything to capitals or to lowercase there is Upper and lowercase. And if besides the capitals your text also has its spaces in disarray, it's worth first running it through Remove extra spaces.