Bartenders generally agree that a one-dollar tip is fine for beer and glasses of wine. However, cocktails are pricier and one dollar is typically too low a tip for a cocktail.

The bare minimum is probably two dollars, but with fancy cocktails at higher prices, you may need to bump that tip up further (the same applies if you're making a demanding order).

A safe bet is to aim for a tip that's around 20% of the drink's price: two dollars for a $10 cocktail, or three dollars for one that costs $15.

For the in-between prices, it's probably better to round down or up to the nearest dollar, as some servers think it's rude to tip with coins.

For cocktails, bartenders need to measure and pour a variety of ingredients, then mix the drink. That's time they can't spend earning more tips, which is why the tip is higher.