If you hate math, traveling overseas might be somewhat of a headache. You knew the balmy reputation of Jamaica before you booked the ticket, yet you packed a couple of sweaters, just in case, when you read the average temperature was 25 degrees. And you had to do a double-take when you noticed the flight departed at 18 o’clock. What the hell is 18 o’clock, anyway?

The United States is pretty much the oddball when it comes to numerical representations—still using weights and measures descended from the British imperial system (pounds, miles, feet and inches), Fahrenheit for temperature, and a twelve-hour am-pm clock instead of the metric system, centigrade temps, and “military time” used all over the rest of the world.

So to keep you on top of the numbers game when traveling abroad, I’ve provided a couple of handy equations that will give you equivalents for the most commonly required measurements. Yes, this involves addition, subtraction, and sometimes, multiplication and division. You might find a calculator to be especially nifty if you haven’t studied any of these operations since the sixth grade.

· Time: The 12 versus 24-hour clock

This one is easy. Most digital clocks outside of the United States (have you ever seen a traditional clock go past 12?) run on a continuous 24-hour time scheme, as does the US military. This means there’s no 6pm. There’s 18:00. The time between 1:00 and 11:59 is automatically considered morning, just as 12:00 until 12:59 is automatically considered afternoon. Once the clock strikes 13:00, the math part comes in. From every hour until 23:59, you’ll have to subtract 12 from the hour slot (18:00 – 12 = 6:00pm). The midnight hour goes from 0:00 to 0:59. Neat, right?

· Temp: Fahrenheit versus Centigrade

A Uruguayan math teacher taught me this trick. If you’re already overseas and the temperature is something like 32 degrees Centigrade, you simply multiply by two, then add 32 for an approximate temperature in Fahrenheit. So, 32 × 2 = 64 + 32 = 96. Don’t be fooled—water don’t freeze at 32°C. For the reverse, maybe 32 degrees Fahrenheit, you have to subtract 32, then divide by two. So, 32 – 32 = 0 ÷ 0 = 0°C. Brrrrr. (For the exact temperature, use 1.8 instead of 2 to multiply or divide).

· Distance: Miles versus Kilometers

Get your calculators out for this one. One mile equals 1.61 kilometers. That means, if the distance between the airport and the nearest Hilton is 100 miles, it is 161 kilometers away. 100 × 1.61 = 161 (I know, I did an easy one). For the reverse, if a distance is 145 kilometers, then you multiply by 0.62 to get the mileage. 145km × 0.62 = 89.9 miles.

· Altitude: Feet versus Meters

This one’s also for the big brains. One foot equals 0.3 meters. Damn. So someone six feet tall is only 1.8 meters (or 180 centimeters). 1 × 0.3 = 1.8. A meter, however, is 3.28 feet. That means if the altitude of a place is 3,000 meters, you’re actually 9,840 feet into the air. 3,000m × 3.28 = 9,840’.

· Weight: Pounds versus Kilos

For the muscleheads, most gyms overseas have weights in both pounds and kilos, and many of your fellow gym rats can give you approximate conversions. But in Brazil, for instance, the gyms feel like they’re far enough away from the United States that they don’t have to use pounds, and you may end up learning the hard way that 20 kilograms absolutely does not equal 20 pounds. The rough conversion is that one pound is almost half a kilo (actually 0.45), while one kilo is a little more than two pounds (2.21 to be exact). Anyone on a structured workout plan, which can be difficult to maintain while on the road, might need exact conversions, as rough approximations can grow rougher rather quickly. A 20-kilo dumbbell equals 44.2 pounds (20kg × 2.21 = 44.2lb), while a 20-pound dumbbell weighs 9 kilos (20lb × 0.45 = 9kg). Gastronomists can also use this equation for buying rice, grains, vegetables and such at super- and flea markets.

Happy measuring.

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another easy way, when it’s in the 30s C to think about how hot it is is to remember that 98.6F [normal body temperature] is 37C. since body temp is 37, i work my 30s range up and down from there. if you were a sickly kid growing up, or spent time in the nurses office for whatever reason, it might have stuck in your head. [32C is 90F, more or less]—the uk still largely uses the imperial system when actually *talking about* weights and measures and distances, but almost everything is labelled in metric, due to EU regulations. so, while odometers and speedometers are in miles, the distances to *exits* on highways are in meters. however, the distances between cities are in miles. nonsensical, i know. you can go to the butcher and say “i want 10 pounds of mince” and the butcher will hear your accent, size you up, and ask “money pounds or weight pounds”? a funny thing when you’re watching the weather report with older presenters there, too. on the weather maps, they will only have celsius. but they will often say “it’s going to be 10 degrees, which is 50 in old money.” old money is a reference to fahrenheit, in this case. but also, the british pound only went decimal in 1971, and a large number of population can actually remember shillings, pence, guineas, and crowns. [and ha’pennies]. it was 240p to one pound, pre-1971. now it’s 100. people who were old enough to be spending money pre-1971 often refer to most imperial measures as “old money”.

Ahhh – I’m totally sure you’ll get this down packed – you’re such the world traveler – one day I’ll be like you – one day!

Are you kidding me? I use all of my limited math ability to convert the pitiful dollar into whatever currency I need. Weights? Degrees? Yeah, okay, thanks. Anyway are you serious about Sao Paulo? Paulistas have a certain dry rep in Brazil but I guess if you’re serious about the business, it’s the place to be. Did you consider Rio? It’s pretty slick but I thought it had more life than Sao Paulo.

And then there’s length, of course.19cm seems to be a fairly standard length, while 21cm+ falls into the range of “dotado”. Yes, 19cm is standard in Brazil.The country is dotado.

Uhhh….thanks for breaking this down. It’ll definitely be a future reference for me. I barely leave my street, lol.