According to a study by Michael Lynn, a professor at Cornell University’s School of Hotel Administration, more than 30 percent of Americans are unaware that tipping 15 to 20 percent of a restaurant bill is the U.S. norm. Imagine the confusion that reigns when we begin crossing borders. It’s essential before leaving home to do some research on tipping practices, but as a general guide, we’ve compiled basic information about tipping in some of the most-visited nations.

Canada and Mexico: Our neighbors to the north and south generally follow the same practices as in the United States, with restaurant servers and taxi drivers alike expecting about 15 percent.

Europe: Many restaurants add a service charge, and it’s customary to add a small amount to that to round up the bill. If you’re really happy with the service, leave a little more. If no service charge is added, shoot for about 15 percent for the tip. Tipping for cabs is more varied among European countries. In Ireland, the average tip is 10 percent, but it’s 13.3 percent in the United Kingdom, and a mere 3 percent in Germany and Greece. Consult a guidebook or Web site.

South America: Restaurants in many South American countries add a service charge of about 10 percent, and a small tip on top of that is generally the norm. In Argentina and Brazil, the total customarily comes out to 13 to 15 percent. In Chile, Peru and Uruguay, 10 percent is average. Ecuador’s norm is a little lower, about 7.5 percent.

There’s an even bigger discrepancy when it comes to tipping taxi drivers. In Argentina, for example, a bit of change will do the trick, while in Brazil, 10 percent is the standard.

Africa: Big continent, big differences in tipping norms among countries. In Kenya and South Africa, a 10 percent service charge is often added to restaurant and bar bills; if not, a voluntary tip in that amount is expected. Taxi drivers also expect about 10 percent. In Morocco, tipping for meals isn’t expected except in high-end restaurants, and spare change or a U.S. dollar bill will please both taxi drivers and bellmen. In Egypt, everyone wants a tip, so keep either dollar bills or small amounts of local currency handy.

Australia and New Zealand: Tipping is not as common as in the States, but the practice is growing in restaurants and bars in larger cities. Taxi drivers do not commonly expect a tip, but you can decline your change.

Asia: If ever you find a country where a tip is refused or even considered an insult, this would be the continent. But you’d be more likely to insult if you failed to tip in Thailand, India, Malaysia, Vietnam and Indonesia, to name a few. In each of those cases, 10 percent is the norm on restaurant bills, and taxi drivers will be pleased with that percentage.

Tipping is not common in Japan, although a service charge might be added to a restaurant bill. Among the countries where tipping is uncommon: Korea, Singapore, Taiwan and Nepal. In China, where tipping used to be unknown, locals in big cities who have been repeatedly exposed to tipping foreigners may expect a monetary thanks.