Is there a way to show limited post length when viewing by categories

I was wondering if I was able to show only the first 100 words or so when viewing the posts by category.

I currently have it set up to show only 5 posts per page, but I would like there to be a limited amount of words shown when viewing by categories, and if people want to read the entire post, they either click on the post, or a read more link.

Is this possible? If so how? I’ve looked through a bunch of settings but can’t figure it out.