increase/decrease (by) ... times

I

Ivvi

New Member
Russian
Dear English speakers,
could you help me decide whether I must use 'by' to specify how much times one number increased / decreased in relation to another number, as in the example below.
To me, it looks like there is substantial difference in the meaning.
The company's revenue increased two times in 2018 = the revenue doubled (eg from USD 1,000,000 in 2017 to USD 2,000,000 in 2018)
The company's revenue increased by two times in 2018 = the 2018 revenue increased BY an amount exceeding the 2017 level twice (i.e. USD 1,000,000 + USD 2,000,000 = USD 3,000,000).
Is this understanding correct or not? Thanks in advance to those who comment.
 
    • "By" is normal after "increase" and "decrease". "By two times" isn't normal. Here is a normal use of "by": Sales increased by 17 percent last year.:thumbsup:

    The company's revenue increased twice/two times last year.:thumbsup: This is an unusual thing to say, but the words and grammar are normal.

    The company's revenue increased by two times last year:confused:
     
    Ivvi said:
    Is this understanding correct or not? Thanks in advance to those who comment.
    Click to expand...
    Your understanding appears to be fine, inasmuch as the second sentence means anything. I strongly suggest only using "by" with percentages or fractions ("increased by 25%" or "increased by a quarter" for instance), and even then being a little cautious with percentages bigger than about 150%.

    Even "increase n times" can be a little problematical in English.

    We almost invariably use "doubled" in your situation, and "trebled" and "quadrupled" where it increased three-fold and four-fold respectively. In general I would say we use terms like "increased five-fold" rather than "increased five times", because "five times" could mean on five separate occasions, rather than five being a multiplier. However, "fold" sounds odd with non-integers, so we use "times" instead, where something like "increased one and a half times" cannot possibly be mistaken for a number of occasions.
     
    The math in your second example does NOT follow the language; 1M + 2M = 3M might be expressed this way: Revenue growth in 2018 amounted to twice the revenue of 2017. 2018 revenue was equal to three times the 2017 revenue.

    For me, without a math term such as “equals”, “two times” clearly means two occasions: I have watched this movie five times. I have visited New York ten times.

    We also hear “increased by a factor of x” which means the new amount equals the old amount multiplied by x.
    Such remarkable growth might be expressed like this: Revenue increased by a factor of 2.5 from 2017 to 2018.
     
    Today I meet the same problem as the poster mentioned.

    e.g. Output of coal increased fourfold last year.

    If the output of coal was 1,000 tons the year before last, How much was the output of coal last year? 4,000 tons or 5000 tons?

    The same problems also happen with these words "increase, decrease, raise, add, reduce".

    e.g. Output of coal decreased fourfold last year.

    If the output of coal was 1,000 tons the year before last, How much was the output of coal last year? 333 tons or 250 tons?
     
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    changwecanbelievein said:
    Today I meet the same problem as the poster mentioned.

    e.g. Output of coal increased fourfold last year.

    If the output of coal was 1,000 tons the year before last, How much was the output of coal last year? 4,000 tons or 5000 tons?
    Click to expand...
    In ordinary English, "increased fourfold" means it is four times what it was, so 4,000 tons in this case. However as you are well aware this does not stand up to logical scrutiny, and the writer would have done far better to write "quadrupled", or use a different expression that did not involve "increased", such as "was four times as high last year", but here you need to add "as the year before", as without "increased" it is not clear what is being compared - it could be four times as high as this year.
    changwecanbelievein said:
    The same problems also happen with these words "increase, decrease, raise, add, reduce".

    e.g. Output of coal decreased fourfold last year.

    If the output of coal was 1,000 tons the year before last, How much was the output of coal last year? 333 tons or 250 tons?
    Click to expand...
    Using "increased" is understandable, even if it may not be technically correct. Using "decreased" with anything other than a numerical value or a proportion less than one is meaningless.

    It could be 200 tons, of course: Starting with 200 tons and treating "increased fourfold" as additive would give 1,000 tons, so "decreased fourfold" could mean the same calculation in reverse. How did you get 333 tons as an option?
     
    Uncle Jack said:
    In ordinary English, "increased fourfold" means it is four times what it was, so 4,000 tons in this case. However as you are well aware this does not stand up to logical scrutiny, and the writer would have done far better to write "quadrupled", or use a different expression that did not involve "increased", such as "was four times as high last year", but here you need to add "as the year before", as without "increased" it is not clear what is being compared - it could be four times as high as this year.

    Using "increased" is understandable, even if it may not be technically correct. Using "decreased" with anything other than a numerical value or a proportion less than one is meaningless.

    It could be 200 tons, of course: Starting with 200 tons and treating "increased fourfold" as additive would give 1,000 tons, so "decreased fourfold" could mean the same calculation in reverse. How did you get 333 tons as an option?
    Click to expand...

    For the first example, I understand your explanation. I mean that "Four times/fold" means the real changed part was 3,000. the result of 1,000 adds 3,000 was the output of coal last year. In order to avoid using "increase" we had better write like this,"Output of coal was fourfold as high as the year before last." It means if the output was 1,000 the year before last, the output of last year was 4,000.
     
    Uncle Jack said:
    In ordinary English, "increased fourfold" means it is four times what it was, so 4,000 tons in this case. However as you are well aware this does not stand up to logical scrutiny, and the writer would have done far better to write "quadrupled", or use a different expression that did not involve "increased", such as "was four times as high last year", but here you need to add "as the year before", as without "increased" it is not clear what is being compared - it could be four times as high as this year.

    Using "increased" is understandable, even if it may not be technically correct. Using "decreased" with anything other than a numerical value or a proportion less than one is meaningless.

    It could be 200 tons, of course: Starting with 200 tons and treating "increased fourfold" as additive would give 1,000 tons, so "decreased fourfold" could mean the same calculation in reverse. How did you get 333 tons as an option?
    Click to expand...

    For the second example, Thank you for showing me the usage of "decrease". Now I know this word can only be used with a numerical value or a proportion less than one. But how should I express the reduction of output from 1000 tons to 250 tons with "xxx times/fold"? I mean that the output from 200 to 1000 means five times/fold, not four times or quadrupled. So I think 200 tons is wrong for "four times/fold".

    My opinion is,"The output of last year is 4 times less than that of the year before last. What I want to tell the readers is "output of last year was 250, output of the year before last was 1,000".
     
    changwecanbelievein said:
    But how should I express the reduction of output from 1000 tons to 250 tons with "xxx times/fold"? I mean that the output from 200 to 1000 means five times/fold, not four times or quadrupled. So I think 200 tons is wrong for "four times/fold".
    Click to expand...
    The output last year was 0.25 times the output of the year before.​
    The output last year was a quarter of the output of the year before.​
    The output last year was 25% of the output of the year before.​
    "Fold" isn't used for fractions (not fractions less than one, at any rate).

    You can use words like "rise" and "fall" or "increase" or "decrease" to make it clear in words which way the change was, but you need to use "to", not "by":
    The output last year fell to 0.25 times the output of the year before.​
    The output last year decreased to 25% of the output of the year before.​
    You can use "fell by" or "decreased by" (with "from" rather than "of") if you quantify the difference between the two values:
    The output last year fell by 75% from the output of the year before.​
    The output last year decreased by three-quarters from the output of the year before.​
     
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