In my language(Serbian) it is normal to say kilo and mean kilogram because the use is most common there and it is like a short version. I know that kilo means one thousand and that it is not correct because kilo is just a prefix but we do it. My question:

Is it in English common (acceptable) to say kilo and mean kilogram?

  • 8
    In the UK and Ireland, it is acceptable to use kilo in place of kilogram. This may not be the case in the USA, since it does not use the metric system, or other English-speaking countries.
    – Mick
    Jan 27, 2017 at 1:09
  • 18
    It would generally be understood in the US (especially since news reports of drug busts often mention kilos of some drugs).
    – Hot Licks
    Jan 27, 2017 at 1:36
  • 15
    @Mick In fairness, the UK doesn't fully embrace the metric system, and the US doesn't fully reject it. British speed limits are in miles per hour, beer is sold in pints, body weight is in stone and pounds, and so on. And in the U.S., many government and industry standards are in metric, only converted to customary units for the delicate sensibilities of the public, thus a bottle of soda identical to one sold in Canada as a 500ml bottle is sold in the U.S. as a 16.9oz bottle, and no one ever asks why the bizarre quantity of 16.9 fluid ounces would have been chosen.
    – choster
    Jan 27, 2017 at 1:52
  • 3
    @choster: If I'm not mistaken, the US was the first country (or at least one of the first) to use a decimal system for money, and it may end up being the last to use a decimal (e.g. metric) system for other measures. Britain is/was a bit the other way around: metric system generally, long ago, money not so much. ;-)
    – Drew
    Jan 27, 2017 at 3:42
  • 1
    @Drew USA: decimal money 1792, later: metric system 1799. ;-) BTW: the US 5 cent coin weight exactly 5 grams Jan 27, 2017 at 6:54

2 Answers 2


Kilo as a short form of kilogram dates back to at least 1870, according to the OED, long before Britain adopted the metric system. You can find it in American dictionaries as well; AHD simply puts it as

ki·lo n. pl. ki·los A kilogram.

and Merriam-Webster consider this its primary definition.

The OED also notes that kilo can be short for kilometre; however, in current usage, this is unlikely to be the assumed meaning outside of narrow contexts. If nothing else, kilo has been reinforced among the public as a unit of mass due to its common usage in television police shows involving drug smuggling.

In more formal communications, I would still advise spelling out kilograms (or using kg) to avoid any ambiguity, however.

  • 6
    Weirdly for distance the single letter k seems to be the most common abbreviation. I ran a 10 k last night.
    – k1eran
    Jan 27, 2017 at 1:51
  • 2
    @k1eran That's true, but much more so for 5K and 10K (common standards) than for arbitrary distances. I've also heard K used for kilograms in a gym context.
    – Chris H
    Jan 27, 2017 at 9:09
  • 2
    I don't know how it is in Serbian, but note that in English you should use the multiple when talking about more than 1 kilogram. So it is "a three-kilo bag" but "the bag weighs 3 kilos". (Just wanted to stress this because in my native language the plural of kilo is kilo).
    – CompuChip
    Jan 27, 2017 at 9:53
  • 5
    @chrylis As an American, I have literally never heard anybody use "klick" outside of military (or paramilitary) contexts.
    – Sabre
    Jan 27, 2017 at 13:29
  • 4
    As an aside, interestingly, the medical professionals around here (NYC, US), particularly veterinary, all seem to say "kigs" for kilograms, as a pronunciation of the abbreviation "kg". I hear this from a wide range of professionals, not just the neighborhood vet or physician, but surgeons, medical directors, committee heads, published authors, etc. I was surprised and confused the first time I heard it, but it pops up consistently in that context.
    – Jason C
    Jan 27, 2017 at 15:03

Yes, Americans know the word kilo. However, this word is not meaningful to them the way it is to you. This is because they don’t have any common reference points that would allow them to immediately understand how much something is in kilos. If you told them something was 5 kilos, they couldn't tell you whether that was like a bag of sweets or a tunafish sandwich or a gallon of milk or a bag of potatoes or can of gas or their mother-in-law. Since nothing is measured in that here, it is just a random foreign number. It would be like telling you that something was 5 acres or 5 feet or 5 ounces: you'd know the word, but the quantity would not be something you could associate with anything concrete in your own life.

So no matter whether you said kilos or kilograms, many Americans would blank if you used these units in your conversations with them. It isn't a unit of measurement that is used here. It's a foreign language.

Some might think when you said kilos, you were talking about kilometers not kilograms, and many would be unable to fathom how much whatever you were talking about really was even if they figured out that you meant mass-qua-weight. They have nothing to compare it with so it’s just random meaningless numbers to them.

You should therefore always convert to American measurements when talking to Americans, just as you would convert Serbian to English. That means you should convert kilograms to pounds.

This does not apply to technical conversations with scientists accustomed to using these units. But the overwhelming majority of Americans will have no idea what you are talking about, just as though you were talking to them in Serbian instead of in English.

  • 8
    At this time, only three countries - Burma, Liberia, and the US - have not adopted the International System of Units (SI, or metric system) as their official system of weights and measures. [...] The US is the only industrialized nation that does not mainly use the metric system in its commercial and standards activities, but there is increasing acceptance in science, medicine, government, and many sectors of industry. cia.gov/library/publications/the-world-factbook/appendix/… It seems a little crazy American general public still using horrendous imperial units :-)
    – k1eran
    Jan 27, 2017 at 1:57
  • 9
    @k1eran What nobody understands is that these are 330 million people who never have to deal with anything else. It's what they've always used. They have no reason to stop when nothing around them is in these foreign numbers, and when most of them will never leave their country anyway. If you don't live here, it is impossible for you to understand how this works to come from a giant country where you never have to use foreign figures. It doesn't matter to them what other people are doing: it does not affect them.
    – tchrist
    Jan 27, 2017 at 2:05
  • 5
    When asking here I was thinking about the "English language" not "in America" :) Of course if I am in a country that uses a different system i will convert.
    – kemis
    Jan 27, 2017 at 2:08
  • 4
    @k1eran It's actually even more complicated, because even in fields like medicine, U.S. conventions may vary from international ones. For instance, serum cholesterol is expressed as milligrams per deciliter in the U.S. whereas it is millimoles per liter elsewhere. And metrication doesn't always simplify things. I spoke to an Australian builder who noted that the standard interior door remains 32×80 inches, except after metrication that became 813×2032mm, which was rounded off in the new standard to 820mm × 2040mm, which means oftentimes, things don't fit quite right.
    – choster
    Jan 27, 2017 at 2:13
  • 10
    This is factually incorrect. 'kilo' is commonly used in the US to refer to drugs. Examples: 1) Methuen police seize 15 kilos of fentanyl, 2) Police Seize 4 Kilos Of Heroin From Bus, 3) York police seize 5 kilos of cocaine. "Police seize kilos" has 770,000 hits, many from US websites.
    – smci
    Jan 27, 2017 at 8:49

Not the answer you're looking for? Browse other questions tagged or ask your own question.