Take a taxi anywhere in South America, and rounding the fare up to the next dollar amount is sufficient as a tip. If you're in an African city such as Cape Town or Nairobi, however, you need to tip 10 per cent for a cab ride.

Going to India? Taking a taxi here means there is no need for gratuity at all.

While even the savviest globetrotter might know the best places to dine and the hippest hotels to stay at, knowing what to tip and when can be downright confounding. Those lucky enough to have the time -- and money -- for a trip abroad this holiday would be smart to heed local custom.

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"Gratuity etiquette perplexes even the most experienced travellers," says Misty Ewing, director of public relations at Virtuoso, a luxury travel network that has travel consultants and ground operators in more than 70 countries. "Everyone has a different interpretation of what's expected and acceptable when showing your gratitude; too much or too little can offend."

At a luxury hotel in Japan, for example, if you try to tip anyone from the wait staff at a top restaurant to the hotel concierge, your gesture will be perceived as a rude and flagrant show of wealth. On the other hand, if you skimp on tipping at any restaurant in the United States or to a concierge who has helped fulfill multiple requests, you probably won't be welcome again.

Top Tips
While these conventions can leave travellers scratching their heads, experts say that there are a few basic rules of thumb to following about tipping.

"In most places around the world, it's better to give something than nothing -- so if you're ever in doubt, tip," says Erica Duecy, editor of restaurants and hotels at Fodor's travel publications. "And in many cases, tipping customs can be broken down by area of the world, so what you're supposed to tip isn't going to vary too much from country to country in that region."

In most countries in Europe, for instance, the service charge is included in the meal; it's customary to add another 5 to 10 per cent for gratuity, especially in high-end restaurants. If no service charge is included, add 15 per cent to the total bill. For taxis, 10 per cent is the right amount to tip, and for hotel porters, give the equivalent of $2 per bag.

Experts agree that when it comes to the concierge at your hotel anywhere in the world, you don't need to tip for advice such as what sights to see; but you should always acknowledge service. In Europe, $2 is enough for each simple request the concierge fulfills, such as arranging airport pickup or making restaurant reservations.

If your concierge is performing special tasks, such as arranging an after-hours tour of the Louvre, it's appropriate to tip $30 or more, depending on the difficulty of your request.

Accepted in Asia
Asia is one part of the world that has slightly different tipping customs for each country.

In Japan, tipping is an insult in any situation; but in China, giving 3 per cent is expected at restaurants, while in Hong Kong, 10 to 15 per cent is the norm if the gratuity isn't included in the bill. For taxis, you don't need to tip in China, but in Hong Kong, you should round the fare up to the next dollar amount.

In both China and Hong Kong, you should give hotel porters $2 to $3 per bag, especially at luxury properties, while $3 to $5 is a good amount for basic requests you ask of the concierge. You should incrementally increase this amount based on the complexity of your request.

What to Do Stateside
It's not always obvious what you need to tip in the U.S. While it's standard to tip 15 per cent at restaurants, if you're enjoying a meal at an upscale spot such as the French Laundry in Napa Valley, it's expected that you'll tip at least 20 per cent.

For taxis in cities such as New York City or Chicago, you should tip 15 per cent, but in smaller cities or towns, you simply need to round up the fare to the next dollar amount. When you check into a hotel, you should give the porter $1 for each of your bags, but if you're staying at an upscale property such as the Four Seasons or the Ritz-Carlton, $2 to $5 per bag is more appropriate. Give on the higher end for especially heavy bags.

When it comes to the hotel concierge, give $3 to $5 for a basic service, such as arranging airport transportation. If the concierge fulfills a more difficult request, like getting you a last-minute 8 p.m. table at a restaurant that is typically booked weeks in advance, it's not uncommon to shell out $20 and up.

Follow these rules, and chances are you'll be less likely to be tripped up while traipsing around.

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In Depth: Global Guide To Tipping