Average Rating Formula

Hey folks.

So this is one of those questions I really feel like I should already know the answer to, so feel free to roast me.

Let’s say you are writing a system that collects user ratings of a thing, 0-5 and you want to average those rating to give the “thing” a single score.

However, you want the number of ratings received to feature, so for example something with 10 ratings of 4 should score higher than a single rating of 5. This, obviously, rules out a simple mean.

How would you approach this? Obviously I can dream up a few ways to do it, but I feel in the back of my mind that there is probably some really simple / standard formula for this kind of thing and I’m just having a senior moment by drawing a blank as to what it is.

Thanks.