Cut off text on homepage?

I’d like to show a post on my homepage in a block that has a set height and width. Is there any way to display part of the post within this box on the homepage with a cut off point so it doesnt strech outside the box?

For example the post would bre cut off at a specific point (after a number of letters or something) so it would appear as:

This is the post, when it gets to a specific number or letters, then the text would ellips with a “…”