Converting to Inches
Measure your height in centimeters. Centimeters are used broadly in Europe, Canada, Asia, and most other countries using the metric system. Though Americans almost always measure height in feet, centimeters are much more common. For example, say you are 180 cm tall. It is almost always easier to convert to inches, then convert to feet later. However, you can directly convert to feet if you have a calculator, which may be more accurate, too. To check your work, know now that 180cm is roughly 5'10 in feet.
Multiply your height in centimeters by .39 to convert your height into inches. There are roughly .39 inches in every centimeter. If you are calculating by hand and need an easier approximation, you could even multiply by .4, though you will not be as accurate. Note that this answer to this equation is always smaller than the original number of centimeters. 180 c m ∗ .39 i n c m = 70.2 i n c h e s {\displaystyle 180cm*.39{\frac {in}{cm}}=70.2inches} 180cm*.39{\frac {in}{cm}}=70.2inches The fraction above stands for "inches per centimeter."
Determine how many 12-inch feet fit evenly into your measurement. There are twelve inches in each foot, and the example has 70.2 total inches. If your divide 70.2 by 12, you get 5.85ft, but be careful -- the decimal is not the number of inches. Since 12 ∗ 5 = 60 {\displaystyle 12*5=60} 12*5=60, and 12 ∗ 6 = 72 , {\displaystyle 12*6=72,} 12*6=72, you know that the height must be above 5ft but below 6ft. So, if you have 5 full feet in 70.2", then 60 of your inches are accounted for. You just have to deal with the last 10.2". 180 c m = 70.2 i n {\displaystyle 180cm=70.2in} 180cm=70.2in 70.2 i n 12 = {\displaystyle {\frac {70.2in}{12}}=} {\frac {70.2in}{12}}= 5' + 10.2
Add the "leftovers" as your inches to get the final measurement. Once you know how many "perfect feet" fit into these inches, just add in the leftover to get your final answer! 180 c m = 70.2 i n {\displaystyle 180cm=70.2in} 180cm=70.2in 70.2 i n 12 = {\displaystyle {\frac {70.2in}{12}}=} {\frac {70.2in}{12}}= 5' + 10.2" 180 cm = 5'10.2
Get more accurate measurements by using the more precise 0.393701 i n c m {\displaystyle 0.393701{\frac {in}{cm}}} 0.393701{\frac {in}{cm}} for your calculations. If you need super accurate conversions, you must use a more accurate decimal for your conversion from centimeters to inches. To see it in action, note how the example above subtly changes. 180 c m ∗ .393701 i n c m = 70.86 i n c h e s {\displaystyle 180cm*.393701{\frac {in}{cm}}=70.86inches} 180cm*.393701{\frac {in}{cm}}=70.86inches 70.86 i n 12 = {\displaystyle {\frac {70.86in}{12}}=} {\frac {70.86in}{12}}= 5' + 10.86" 180cm = 5'10.9
Converting Directly to Feet
Multiply the number of centimeters by 0.0328084 to get the height in feet. This is a direct conversion, though it does not tell you the number of inches, directly. Instead, it tells you the number of feet -- so an answer of 6.25ft doesn't mean someone is "six feet, 2.5 inches." It means he is "six and a quarter (25%) feet tall," or 6'3". Continuing the example from other methods: 180 c m = 180 c m x 0.0328084 f t c m = 5.905512 f t {\displaystyle 180cm=180cmx0.0328084{\frac {ft}{cm}}=5.905512ft} 180cm=180cmx0.0328084{\frac {ft}{cm}}=5.905512ft 180 c m = 5.905512 f t {\displaystyle 180cm=5.905512ft} 180cm=5.905512ft
Separate the decimal out if you want to get the precise number of inches. The integer, the whole number in the beginning, is the number of feet (in this case, 5). The decimal is the percentage of a foot added on. But this number isn't really helpful, since we never say "he is 5.9 feet tall." We give inches. Separate the two to begin to simple process. 180 c m = 5.905512 f t {\displaystyle 180cm=5.905512ft} 180cm=5.905512ft 180 c m = 5 f t + .905512 f t {\displaystyle 180cm=5ft+.905512ft} 180cm=5ft+.905512ft
Multiply the decimal by 12 to convert it to inches. There are 12 inches in every foot, but you need to find out how many inches are in .905512 feet. To do so, simply multiply. If you have trouble remembering why, think about what you would do if you had 1 foot, and needed to know how many inches there were: 12 i n ∗ 1 f t = 12 i n c h e s {\displaystyle 12in*1ft=12inches} 12in*1ft=12inches. What if it was 6: 12 ∗ 6 = 72 i n c h e s {\displaystyle 12*6=72inches} 12*6=72inches. Now, what if the number was smaller than one, like .905? It's the same philosophy -- you get your inches based on the number of feet by multiplying by 12. 180 c m = 5.905512 f t {\displaystyle 180cm=5.905512ft} 180cm=5.905512ft 180 c m = 5 f t + .905512 f t {\displaystyle 180cm=5ft+.905512ft} 180cm=5ft+.905512ft 12 i n f t ∗ .905512 f t = 10.9 i n c h e s {\displaystyle 12{\frac {in}{ft}}*.905512ft=10.9inches} 12{\frac {in}{ft}}*.905512ft=10.9inches
Add your inches back to your total feet to get your converted height. Simply add back in the integer (the number before the decimal) with your new inches calculation. You've converted! 180 c m = 5.905512 f t {\displaystyle 180cm=5.905512ft} 180cm=5.905512ft 180 c m = 5 f t + .905512 f t {\displaystyle 180cm=5ft+.905512ft} 180cm=5ft+.905512ft 12 i n f t ∗ .905512 f t = 10.9 i n c h e s {\displaystyle 12{\frac {in}{ft}}*.905512ft=10.9inches} 12{\frac {in}{ft}}*.905512ft=10.9inches '180cm = 5' 10.9"
Estimating the Conversion Accurately
Use simple percentages to get a basic estimation if you don't have a calculator. Remember that one centimeter equals roughly .39 inches. For estimation purposes, this means your height in inches is roughly 39% of your height in centimeters. To make this easier, round up to 40%. Now, since percentages in multiples of ten are so easy to figure out, you can get a quick approximation of your conversion. Remember that 10% of any number simply moves the decimal one move to the left. Percentages always add to 100%, but can also be added anywhere in between. Thus, if you need to figure out 40% of a number, you can add 10% + 10% + 10% + 10%.
Multiple your height in centimeters by .10, or 10%. This will give you one tenth of your height. To do so without a calculator, simply move the decimal one place over to the left. Thus, 100 → 10, 9.2 → .92, and .421 → .0421. To continue a common example: 180 c m ∗ 10 % = 18 c m {\displaystyle 180cm*10\%=18cm} 180cm*10\%=18cm Don't forget that 10% = .10, as percentages are just another way to write decimals (ie. 40% = .4, and 59% = .59, etc.)
Multiply your 10% answer by 4 to estimate your height in inches. You have 10% of your height, but you need to estimate 40% of it. You can turn 10% into 40% by multiplying by four, and it doesn't matter what your actual percentages are. Simply substitute in your number from before and multiply by 4: 1 c m = 40 % i n {\displaystyle 1cm=40\%in} 1cm=40\%in 180 c m ∗ 10 % = 18 {\displaystyle 180cm*10\%=18} 180cm*10\%=18 10 % + 10 % + 10 % + 10 % = 40 % = 10 % ∗ 4 {\displaystyle 10\%+10\%+10\%+10\%=40\%=10\%*4} 10\%+10\%+10\%+10\%=40\%=10\%*4 18 ∗ 4 = 72 i n {\displaystyle 18*4=72in} 18*4=72in
Divide by 12 to determine how tall someone is in feet. If the number doesn't go in evenly, simply divide it as close as possible, then add in the remaining inches by feet. So, if you get 50 inches, you would have 4 feet, with two inches left over. The person is 4'2. In the example, the answer is 72 inches, or exactly 6 feet, since 72 divided by 12 is 6. This division doesn't have to be hard, since there are really only a few options for human height: 12 inches = 1 foot. 24 inches = 2 feet 36 inches = 3 feet 48 inches = 4 feet 60 inches = 5 feet 72 inches = 6 feet 84 inches = 7 feet
Alternatively, divide your 10% answer by 3 to get your rough height in feet. Remember how 1 centimeter converts to .0328084 feet? Just like any other decimal this can be converted to a percentage, meaning 1 centimeter is actually 3.3% of each foot (note: you convert a decimal to a percentage by multiplying it by 100). And, if you divide 10% by 3, you get roughly 3.3%. Now, just substitute your actual percentage for 10% in this equation and you have your estimation! 1 c m = 3.3 % f e e t {\displaystyle 1cm=3.3\%feet} 1cm=3.3\%feet 180 c m ∗ 10 % = 18 {\displaystyle 180cm*10\%=18} 180cm*10\%=18 10 % 3 = 3.3 % {\displaystyle {\frac {10\%}{3}}=3.3\%} {\frac {10\%}{3}}=3.3\% 18 3 = {\displaystyle {\frac {18}{3}}=} {\frac {18}{3}}= 6 feet, or 72 inches Remember that a decimal in the answer is not the number of inches. To get that, multiply any remaining decimal by 12.
Understand that these estimations will always come out a little taller than reality. Remember the original estimation for centimeters and inches? You converted .39 to 39%, which was then rounded up to 40%. While this makes the solution easier, it slightly overestimates the conversion by adding this percentage point. As a result, you should know that all estimations will be just a touch higher. You can make this slightly more precise by subtracting 1% from your initial number. So, instead of using 180cm, use 178.2cm. This is extra helpful if, instead of 180 cm, you get something more difficult, like 182cm. Knowing it will overestimate, cut it to 180. When using precise decimals, 180 cm = 5' 10.9". When estimating using the above methods, 180 = roughly 6 feet. They are only about an inch off -- but they are still different.
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