A trip across the Pacific will guarantee you a different experience with a tipping culture you've never come across in China．

In the US，giving a little extra money to service workers on top of your bill is a common practice．

Though US national law requires that businesses pay workers at least 7.25（45yuan）perhour，employeesreceivingtips-oftenwaitersandwaitresses-aretheexceptions．Theyusuallyonlyreceiveatleast2.13an hour，and tips make up the difference．As the Wall Street Journal put it，"The American system of tipping holds the promise of great rewards for waiting staff．"

So how should you tip if you are in the US？

Normally you pay tips as a percentage of the bill．Offering an extra 15percent of the bill to the waiter or waitress in a restaurant and to the delivery man or woman is customary and expected．You can offer more for great service and less for poor service．

Yet there is an exception．For take-out food，you don't have to provide tips，though some people say that filling an order still requires work and time that deserve a little extra-but maybe a little less．

Tips are not expected at fast food restaurants，cafés or ice cream shops either，though a tip jar might be right by the cash register （收银机）．Don't feel obligated to throw some money in，but also remember that it doesn't hurt．Those workers do not rely on tips．

Other service workers also receive tips．For taxi drivers，15percent is the norm （标准），more if they help with your bags．Hairdressers often receive about 15percent of the bill．The same goes for spa therapists and tour guides．

Today，you can even pay tips on a credit card．When receiving a copy of the bill to sign，you are free to fill in how much you'd like to tip．

Though thinking about when to tip and how much you should tip causes a big headache for many Chinese people，it's important to bear in mind that as long as you show respect and use your reasoning，things wil