When do I need to put "on" after "improve"? I have seen things like

"He has improved his conversational skills this semester a lot."

and I have also seen things like

"He has improved on his previous results in this subject's tests."

So, I am at loss here as to when "on" is needed in such cases and when it's not.

  • In the given cases, both are acceptable. HMB while I think of some where it doesn't work. Apr 16, 2018 at 2:36
  • @Blacksilver - What do you mean by "HMB"?
    – brilliant
    Apr 16, 2018 at 3:06
  • Hold My Beer. Apr 16, 2018 at 3:07
  • @Blacksilver - Does that mean that it's rather hard for you to think of an example where it doesn't work (which means that there probably aren't any such cases), or does it mean that you would rather not bother to think of an example where it doesn't work?
    – brilliant
    Apr 16, 2018 at 3:11
  • Man, this deserves it's own question. It means it's hard... I geuss? It really depends on context. Apr 16, 2018 at 17:38

2 Answers 2


Just as in your examples, you would use

He has improved on his personal best time over the past year.
Ha has improved upon his personal best over the past year.

when you are talking about a specific level of improvement, whereas

He has improved his running times over the past year.

describes a general amount of improvement.


"Improved X" means "made X better".

"Improved on X" means "got something better than X".

There can be some overlap. For example, if I improve on my personal best time, it means that I get a time better than my previous best time which is the same as improving my best time. On the other hand, if I improve on your best time, I get a better time but it doesn't improve your best time.

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