# 公里 / 千米



## 奥利弗

Hi everyone,

is there any difference in usage/register at all between 公里 and 千米 for kilometer? Is it maybe like 角 and 毛？

Thanks!


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## OneStroke

In my experience, the only difference between the two is that 公里 is way more common that 千米 where I live. Both are officially recognised (unlike, say, 公尺 or 公厘, which aren't).

By the way, there's an appendix at the end of the Xiandai Hanyu Cidian about units. It's a good reference.


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## BODYholic

奥利弗 said:


> Hi everyone,
> 
> is there any difference in usage/register at all between 公里 and 千米 for kilometer?



I think it works the same in English too. For example, there are race events known as 3000m relay (instead of 3km relay). In Chinese, it would be 三千米接力赛 and rarely 三公里接力赛.


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## Elzza

In colloquial Mandarin, "公里" is more frequently used than "千米''. 
If we use ">" to indicate that the former is more frequently used than the latter, then also 公分>厘米，公斤>千克, but 米>公尺(in fact, 公尺 is rarely used now).
In the old days, there was only one set of measurement. Later, foreign measurement came into use too. Therefore, to name the foreign measurement people add "公"(which means "public" in this case) in front of the old measurement. For instance, "里" belongs to local measurement. In order to name a new measurement, "公里" is adopted.


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## SuperXW

I agree with Elzza.
千米 appears more on formal written materials.


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## Youngfun

千米 is the official name for km, as it is formed regularly according to the SI international naming conventions: 千 + 米, an exact translation of kilo + metre.
And so the official names are 厘米、千克、米 etc. 
These are the forms taught in schools.

But in Taiwan 公尺 is more frequent than 米.

But in China, groceries are still priced per jin (500 g), but because the jin is not an official measure unit, they write 500 g instead, e.g. 10 Yuan/500 g. Usually 500 g written very small or entirely omitted.
But scales measure in kg! At the beginning I always got confused at supermarkets when I see the label on fruit and vegetables after weighed them... I thought they charged me the double 

It seemd that in Taiwan the traditional measure units such as 两、斤、尺、寸 have retained their original values.
While in Mainland China they have changed to a value more easy to calculate when converting to international units, so 两 is 50 g, 斤 is 500 g (half kilo), 尺 is 1/3 m, and 寸 1/3 of 10 cm.
It's very interesting seeing Taiwanese come to Mainland for groceries, and after asking for price, they ask: how many grams are in 1 jin?


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## BODYholic

Youngfun said:


> But in China, groceries are still priced per jin (500 g)



Strangely though, a catty (斤) is always understood as 600 grams in Singapore. But I have to say that this is an extremely rare unit of measurement here. Probably only our Chinese medical halls still use it.


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## Youngfun

Yep, that's the original value of the catty.
According to Wikipedia, a catty is about 0.60478982 kg in Hong Kong (this should be the most accurate value).

In Singapore it's 1 pound and 1/3:


> 新加坡斤：1斤约等于604.8克
> 
> 新加坡法律规定一斤为11⁄3常衡磅，等于十六两，即0.6048 公斤[3]



All Asian countries, including Hong Kong, Taiwan, Singapore, Malaysia, Vietnam use the traditional value (with different degrees of approximation), only Mainland China has changed the value to 500 g.
While Japan has rounded to 600 g.

See: http://zh.wikipedia.org/wiki/斤


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## SuperXW

计量单位在各地、各时代不统一，的确是非常让人头疼的事。不止汉字文化圈这样，英美也麻烦得很。暂时没啥办法，只能入乡随俗了。


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## Youngfun

美国比较固执，不用国际单位。
英国则国际单位和帝国单位混用……导致情况更混乱……


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## OneStroke

Youngfun said:


> 千米 is the official name for km, as it is formed regularly according to the SI international naming conventions: 千 + 米, an exact translation of kilo + metre.
> And so the official names are 厘米、千克、米 etc.
> These are the forms taught in schools.



According to the appendix at the end of the Xiandai Hanyu Cidian, 公里 seems to be an exception in that both 千米 and 公里 are officially accepted forms.


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## Youngfun

Well, 现代汉语词典 is considered the authority of the Chinese language, then I must agree with you. 
So... it accepts 公里 but not 公斤、公分、公尺  ect.?

But I still think 千米 would be the preferred form in formal contexts. In scientific or technical texts/documentaries you are more likely to read/hear 千米 than 公里。


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