You want to get the most from your drinking, right?
That means maximizing the booze you have on hand, via math. (Note: Figure this out before you drink.)
In service of that, VinePair has broken down how many drinks each bottle of alcohol yields. Their chart uses alcohol by volume (ABV) and bottle size (750 mL, 1.5 L, etc.) to determine the quantity of drinks per bottle, with the understanding a standard drink has 14 grams of pure alcohol. So a spirit with a 40 percent ABV nets in a 1.75 L bottle nets you 40 drinks, a standard bottle of wine nets you five, and so on.
Hopefully, you aren’t basing your drinking purely on efficiency. Still, the chart has uses: if, say, you’re figuring out how much you’ve had to drink for dietary or driving purposes. To that end, we’d also suggest the the Rethinking Drinking Calculator, which gives you a more exact figure and breaks down the booze into more specific categories beyond beer, liquor or wine.
Another (and definitely more fun) use: parties. If you’re trying to figure out booze allotment for a large gathering, you can use the VinePair chart (The Kitchn also has a simple, similarly math-flavored breakdown of your booze needs).
Otherwise? Drink what you like and stop when it feels bad. No calculations needed for that.