Chances are, it's about 20 percent. But when it comes to other questions about tipping, most of us don't have a ready answer. Steve Dublanica, a former server and author of the blog "Waiter Rant" and the book "Keep the Change: A Clueless Tipper's Quest to Become the Guru of the Gratuity," talked to Reader's Digest and answered several puzzling questions about tipping etiquette.
Should you tip on the tax?
The answer: Since the restaurant doesn't get to keep the tax money, there is no reason to tip on the tax. Even restaurants think that way, since they don't include the tax when they tally the tip for a large party. The gotcha: At the end of the shift, servers tally their total sales, tax included, for a "cash-out" amount. Based on that amount, they pay some of their tip money to the busboys, runners and other restaurant staff. By not tipping on the tax, you're not giving the servers their fair share.
What is the correct amount to tip on drinks?
The answer: The conventional wisdom is that tipping 20 percent on a drink is way too much. The standard in most bars is $1 or 10 percent. Besides, bartenders receive tips from other members of the restaurant staff. The gotcha: Bartenders do more work than servers because they actually make the drinks. So when you look at it that way, they deserve 20 percent. Be generous. Tip 15 percent to 20 percent for drinks.
Should you always tip the barista?
The answer: Why not? They're skilled food-service workers and deserve tips. The gotcha: You may not realize it, but baristas are paid a decent hourly wage, unlike restaurant employees. So baristas don't work for tips. If you're only getting a cup of the house blend, don't tip. But if you order a complicated frothy latte drink, throw in some change or even a buck.
Is it ever acceptable to leave a bad tip?
The answer: No. Even if your server does a horrible job, other employees of the restaurant are also working to make your experience enjoyable. When you stiff your server, you're stiffing them, too. The gotcha: If you receive bad service, it is your right to leave a bad tip, since it does send a message of displeasure to the management. Or do this instead: Ask to see the manager and explain--politely!--why you are unhappy.