I'm going to New York City soon for business, and I will probably be using taxis frequently to get around. Is there a certain expected tipping percentage for NYC cab drivers?
I usually round up to the next 5 dollar increment, with a minimum of 15%. If paying by credit card, I'll usually just use the automatic 20% button (the smallest offered), out of laziness.
This WSJ Article claims that the average in NYC is 18-19%. Which is above the national average by a little, but not much. That's a pretty decent number to target, but I'll often come in a bit above or below it because it's just so much easier to hand over a 20 dollar bill and say 'keep the change' on a 15.50 fare.
Keep in mind, your cab driver derives more than a quarter of his income from your tips. Feel free to toss them an extra couple of bucks if they do things like help with your luggage, or if you're asking them to drive you someplace where it'll be difficult to pick up their next fare, like Queens.