Text-to-Speech character limit?

Not that I've reached the limit but this question was posed to me recently. I can't seem to find any specifications anywhere. Thanks in advance!

Greetings, Kevin!

Is there a limit to how many characters you can have in text-to-speech?

Good question! You can convert up to 10,000 characters at a time.

✎ Note: The more characters there are, the longer it might take to convert.