Though common advice says to tip 15 percent to 20 percent, it may not always be obvious how much to tip for a service — or ...

Rather than the simple 20 percent tip he would often pay, the diner was horrified to calculate that it was actually a 72 percent tip.

a flat tip per item may be more appropriate than a percentage. How much to tip bartenders: About $1 to $2 per drink or 15% to 20% of the tab, according to the Emily Post Institute. If you order ...