Dictionaries list "completion" as a definition for both of these words. I'm trying to figure out the difference between them.

Some online sources say 完成 is used when you finish making something and 完了 is used when you are finished doing something, but I'm kind of skeptical about this because I've seen sentences with 完成 used with 仕事, such as this one:

The work has been almost completed.

What's the difference between them?

  • Note that in English too, one can be finished doing something without yet having completed that same something. Oct 10, 2015 at 3:35
  • That's true, but I assumed both 完成 and 完了 did imply completeness due to the 完 kanji (and the dictionaries). Was my assumption wrong?
    – Blavius
    Oct 10, 2015 at 3:43
  • I admit it's possible that I might have the wrong end of the stick. I'll sit back and await clarification from others. Oct 10, 2015 at 3:45
  • This example does not disprove the theory. If you build a match house, you can call the whole task a "work" (仕事) and claim it was almost completed. Don't you?
    – macraf
    Oct 10, 2015 at 3:47
  • 2

3 Answers 3


完成 & 完了 have almost the same meaning, but there is a slight difference. According to my Chinese character dictionary the character "完" means "completeness", "成" means "forming and making something", and "了" means "arranging and finishing something".

For example, I would say "車のタイヤの取り付けが完了した" (="I finished attaching tires to a car") even though I have not produced a complete car. But it's a little weird to say "タイヤの取り付けが完成した". If I finished all the processes of producing a car, I could say "車が完成した" but not "車が完了した". So, I think 完了 is used for finishing tasks, and 完成 is for finishing making something.

The sentences, "仕事が完成した" and "仕事が完了した" are both correct because 仕事 is something to make and achieve, and also a task.

(My mother tongue is not English so please feel free to ask if you are not sure about my answer.)


完成 means something has been physically assembled.

完了 is a completion of a process.

They are interchangeable when you are talking about a long process that puts something together, like construction of a building. Otherwise, only one or the other will do.


仕事 that corresponds with 完了 means human activity while one that corresponds with 完成 means products. In other words, when the work is constructive activity, what 完了 and 完成 stand for is a similar thing. But when the work is destructive one, using 完成 is not natural though you may be able to use it sarcastically.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .