Our friend the metric system

Converting between American and metric measurements: miles and kilometers, feet and meters, pounds and kilos, gallons and liters, Fahrenheit and Celsius (plus a few others)

Remember back in the 1970s when we were all going to go on the metric system? What ever happened to that? Oh, yes: Reagan.

Whether you need to figure out how far 150km is in miles (93), how many centimeters in a foot-long hot dog (30cm), how to order a half a pound of cheese for your picnic (225 grams), or just how ridiculously hot 40° Celsius is so you can complain in your postcards home (105° F), here are the answers.

If you're wondering what your size 12 American body is to that little black dress in a Paris boutique (now don't faint, but here you're a size 42), or whether your size 10 feet need a 35 or a 55 in a handcrafted Italian leather shoe (neither; you’re a 44), that's all on a different page of clothing sizes.

You say kiLOMeter, I say KILometer

At least these are easy enough to do in your head. A kilometer (km) is equal to 0.62 miles, and a mile is 1.61 km.

Km	Miles
1km	0.62mi
2km	1.24mi
3km	1.86mi
4km	2.46mi
5km	3.11mi
6km	3.37mi
7km	4.35mi
8km	4.97mi
9km	5.59mi
10km	6.21mi
50km	31.07mi
100km	62.14mi

Miles	Km
1mi	1.61km
2mi	3.22km
3mi	4.83km
4mi	6.44km
5mi	8.05km
6mi	9.66km
7mi	11.27km
8mi	12.88km
9mi	14.48km
10mi	16.09km
50mi	80.47km
100mi	160.9km

OK so it's not THAT easy. Still, doing a rough calc in your head isn't that hard. For kilometers to miles, just break it into two bits: 50% plus 10% (which totals 60%, or 0.60), then round up a smidgen for that extra 2% (the 0.02).

That sounds more complicated than it is: The road signs says Siena is 80 km away. OK, so to get 50% you just cut that in half, which is 40. Tuck that away in a crevice of your cerebellum for a moment.

Now take 10% of the original 80—which is 8—then add that to the 40 and you get 48. Round up "a smidgen" to cover that extra 2% and you get 50. That means 80 km is roughly 50 miles (actually, it's 49.6, so close enough). Here, I'll make it easy for you with the table up to the right.

Frankly, you'll rarely ever need to convert the other way, unless you want to say to someone in Europe something along the lines of "I live 20 miles outside of Boston," only put it in kilometers terms so he understands where your suburb is. No biggie. Ten miles is about 16 kilometers, so tell him you live 32 km from Boston. (This is assuming, of course, he has more than a vague sense of where Boston is in the first place.) That cheat sheet is also above to the right.

The yardstick by which meters are measured

Thank heavens for the yardstick. You can point with it, you can rap people in the knuckles with it, you can even measure stuff with it, so long as the stuff in question is less than three feet long.

And it's also about one meter long, so just picture a yardstick and you know what a meter looks like. Well, roughly.

Actually, 1 meter is 3.3 feet—a bit longer than a yard. So 10 meters is equal to 33 feet, or 11 yards, which is enough for a first down (only they play soccer in Europe, so that little joke wouldn't work). 100 meters is 330 feet (or 110 yards), 1,000 meters is 3,300 feet (or 1,100 yards). One thousand meters is also 1 kilometer, which is 0.62 miles; see above.

Give a man an inch, he'll take about two and half centimeters

Cm	Inches
1cm	0.4in
2cm	0.8in
3cm	1.2in
4cm	1.6in
5cm	2in
6cm	2.4in
7cm	2.8in
8cm	3.2in
9cm	3.6in
10cm	3.9in
11cm	4.3in
12cm	4.7in

Inches	Cm
1in	2.54cm
2in	5.08cm
3in	7.63cm
4in	10.16cm
5in	12.70cm
6in	15.24cm
7in	17.78cm
8in	20.32cm
9in	22.86cm
10in	25.40cm
11in	27.94cm
12in	30.48cm

I can't think of a time when I've had to use inches or centimeters in any discussion in Europe, much less needed to convert between the two, but just to be thorough:

One inch is equal to 2.54 centimeters (make it two and a half).

One cm is 0.4 inches.

That means 12 inches is 30.48 cm (just pretend it's 30). We call that "a foot," but Europeans don’t have a separate word for something of that length; they'd just say "30 centimeters" or maybe "a third of a meter."

Then again, since they don’t eat hot dogs (just würstel), I guess they don't need a term for foot-long.

A gram of prevention is worth a kilo of cure

Pound	Kg
1lb	0.45kg
2lb	0.91kg
3lb	1.36kg
4lb	1.81kg
5lb	2.27kg
6lb	2.72kg
7lb	3.18kg
8lb	3.63kg
9lb	4.08kg
10lb	4.54kg
50lb	22.68kg
100lb	45.36kg

Kg	Pound
1kg	2.21lb
2kg	4.41lb
3kg	6.61lb
4kg	8.82lb
5kg	11.02lb
6kg	13.23lb
7kg	15.43lb
8kg	17.46lb
9kg	19.84lb
10kg	22.05lb
50kg	110.23lb
100kg	220.46lb

Unlike the U.S., where only cocaine ever comes in kilos, in Europe you'll be ordering lots of (perfectly legal) things by the "key."

Actually, when it comes to food you'll more frequently order by the gram, because who needs 2.2 pounds (1 kilo) of anything?

Conveniently enough, 100 grams is just about the perfect amount, per person, of cheese, salamis and other cured meats, fruit, or whatever else you desire in putting together a picnic. Heck, it's so perfect the Italians even have a special term for 100 grams: un etto.

No, you don't order a "112.5-grammer" at McDonald's in Europe; they know what a "Quarter Pounder" is. However, if I catch any of you giving into temptation and ducking into that McDonald's while you're in a foreign country, so help me I'll verbally thrash you to within an inch...er, 2.54 centimeters...of your greasy fries-addicted life.

Actually, this point was brought up by a greengrocer arrested in Britain a few years ago when jolly old England finally decided to crack down and force feed the metric system to its people. The bloke was still selling his bananas by the pound, not the kilo, at a local market so he was hauled off and fined.

The jovial fellow became something of a minor cause cèlèbre, the "Metric Martyr," and was fond of pointing out the hypocrisy that they would persecute a small fry like him when McDonald's was left to flagrantly flout the new laws by refusing to rename the Quarter Pounder.

Wine is not sold by the quart

Gal	Liter
1gal	3.79L
2gal	7.57L
3gal	11.53L
4gal	15.14L
5gal	18.93L
6gal	22.71L
7gal	26.50L
8gal	30.28L
9gal	34.16L
10gal	37.94L
50gal	189.7L
100gal	379.4L

Liter	Gal
1L	0.26gal
2L	0.53gal
3L	0.79gal
4L	1.06gal
5L	1.32gal
6L	1.58gal
7L	1.85gal
8L	2.11gal
9L	2.38gal
10L	2.64gal
50L	13.2gal
100L	26.4gal

Actually, it kinda is—sold by the quart, that is.

One liter equals roughly a quarter of a gallon (i.e. a quart). Not that you'll catch any Italian or Frenchman using such a barbarous term. No, they drink wine by the liter over there, that you very much—which may explain why they're so happy much of the time.

OK, so bottles of wine are actually usually 0.75 liters, not full liters, but let's not quibble.

If that's too much vino for your blood, you can always order table wine by the half-liter (about four glasses-worth, called un demi in French and mezzo litro in Italian) or quarter-liter (two glasses; un quart in French, un quartino in Italian).

You give me fever

° F	° C
32	0
40	5
50	10
60	15
65	18
70	20
75	25
80	27
85	30
90	32
95	35
100	38

Tell a doc in Italy that you're running a fever of 102°, and he won't believe you—because 102° Celsius is equivalent to 216° Fahrenheit, which means your brain would be fried faster than that egg in the old "...this is your brain on drugs" commercial.

And if the local news reports that tomorrow's temperature will be around 32°, that's means it'll shorts and T-shirt weather, not down parka time—32° degrees Celsius is 90° Fahrenheit.

The bad news: there is no simple formula to convert Celsius to Fahrenheit and back. There is a formula, of course, but it ain't the sort of thing you'd want to do in your head. Take the Celsius amount, multiply it by 1.8, then add 32. See, wasn't that easy?

If math is one of the things you're taking a vacation from, the chart on the right can help you ballpark things.