Yep, and it's great. Beyond ads, you can also configure it to block malware. Got a phishing email from scammer.ru? Nothing happens even if you to click the link in it because that name won't resolve. There were a very short list of exceptions, maybe 2 or 3, I had to add to ours over the years, mainly for hostnames like tracking.shippingcompany.com that got added by mistake.

Note that it does nothing to block DNS over HTTPS lookups. If your browser insists on going around your LAN's DNS setup, Pi-hole can't help you.