There is some dispute about what constitutes an appropriate bar tip. When people pay for drinks one at a time, they usually tip the bartender about $1 US Dollar (USD) per drink. Free drinks delivered in a casino setting tend to require a tip of $1 to $2 USD.
When a person has a tab at a bar, usually a tip is calculated as 15-20% of the total cost before tax. If it is happy hour, the tip should be calculated toward the higher end, since the drinks are being offered at discounted prices. For example a tip on a “buy one, get one free” offer should reflect the total price of the drinks prior to the discount. The bartender is still serving two drinks, and it is unfair to tip him or her for only one.
There is some confusion about what to do if the bartender is also the proprietor of an establishment. It used to be the custom never to tip the owner since he or she has a greater share of the ultimate profits of the restaurant. This custom is now being replaced by in general tipping anyone who serves one a drink at a bar. Often it is hard to know if a person is the owner or not, and of course, a generous tip at a place a person frequents may result in free drinks down the line.
Sometimes, a proprietor will refuse a tip, or may give the money to employees as part of their nightly take. For etiquette’s sake, unless a customer knows the proprietor won’t accept a tip, it is always appropriate to offer one.
When a person attends a wedding with a bartender, even if the drinks are free, the standard bar tip is still $1 USD per drink. Some feel this violates etiquette by requiring an invited guest to offer a tip to the bartender. In reality, a tip is not required of the guest, but neither is ordering a complex drink. Offering a tip at a wedding or similar celebration is simply a mark of good manners.
Most bartenders make the majority of their earnings through tips, and this is no less true at a wedding or special event. Though the bartender is likely to be paid slightly more than minimum wage, it is still a nice gesture to recognize the work involved and accordingly give a decent tip.