Serious Eats - seriouseats.com

I have a slightly different question: I grew up knowing that tipped employees were paid only a fraction of minimum wage and had a 10% (terrible service) min tip with a 20% (good service) standard, but here in SF wait staff is paid the city minimum wage (higher than the national min wage) and most restaurants add a health care cost surcharge to support the city's universal health care coverage. I really think tipping in excess of 15-20% is extreme in this situation.

Also, many restaurants that add tip have started adding the tip (usually a few percent higher than 15%) to the total bill, not the pre-tax amount. which increases the tip by ~10% or >1.5% of the bill. If the service is especially good I usually add a bit more in addition to the pre-determined amount, but not if the tip is based on something other than the food and beverages ordered.

That being said, whenever I eat out with a friend who i know under-accounts for tip and tax when figuring their share of the bill, I always pay with cash and throw in a few extra bucks. BistroMath never ceases to amaze!