〜きる: Doing Something Completely / To the End
The thoroughness it lays on the verb
〜きる (written 〜切る as a suffix) is built from the verb 切る ("to cut"), but bolted onto another verb it no longer means cutting. Instead it adds a layer of thoroughness — not just doing something, but doing it all the way. That extra meaning shows up in two related shades:
- An action carried through completely — to the very end, with nothing left over.
- A state reached fully / to the extreme — being in a condition utterly, completely.
ヤッタンは大盛りのカレーを食べきった。
ヤッタンは おおもりの カレーを たべきった。
Yattan ate up the whole large serving of curry.
食べる + きる = eat it all, leaving nothing.
モチはマラソンを最後まで走りきった。
モチは マラソンを さいごまで はしりきった。
Mochi ran the marathon all the way to the end.
走りきる = run completely to the finish.
先生は疲れきった顔をしていた。
せんせいは つかれきった かおを していた。
The teacher had a completely exhausted look on her face.
疲れきる = be utterly worn out — a state taken to the extreme.
Which verbs it attaches to
Take the verb's ます-stem (the form before ます) and attach きる. The whole thing then conjugates as a regular う-verb (it ends in る but behaves like 切る → 切った, 切って), so the past is 〜きった and the て-form is 〜きって:
| Verb | ます-stem | + きる | Meaning |
|---|---|---|---|
| 食べる (eat) | 食べ | 食べきる | eat it all up |
| 使う (use) | 使い | 使いきる | use up entirely |
| 読む (read) | 読み | 読みきる | read all the way through |
| 疲れる (tire) | 疲れ | 疲れきる | be utterly exhausted |
Not every verb welcomes it: 〜きる wants verbs with a natural endpoint or limit — food, distance, supplies, energy. 死にきる or 知りきる sound odd, so reach for it only where "completely / to the end" genuinely makes sense. Because the whole cluster behaves like an う-verb, it also stacks cleanly with other auxiliaries:
貯金を使いきってしまった。
ちょきんを つかいきって しまった。
I ended up using up all my savings.
使いきって + しまった — stacks naturally with 〜てしまう.
The negative 〜きれない in use
The potential-negative form 〜きれない ("cannot finish …-ing" / "too … to …") is at least as common as the positive. It says the action is too much to complete — and because きる is an う-verb, this is its potential negative (きれる → きれない), not "can't cut":
量が多すぎて、一人では食べきれない。
りょうが おおすぎて、ひとりでは たべきれない。
There's too much — I can't finish it on my own.
食べきれない = can't eat it all up.
弟は覚えきれないほどの単語を一晩で出された。
おとうとは おぼえきれない ほどの たんごを ひとばんで だされた。
My little brother was given more vocabulary words in one night than he could possibly memorize.
覚えきれないほどの = more … than one can memorize.
The pattern 〜きれないほどの + noun ("more … than you can …") is a set phrase worth memorizing: 数えきれないほどの星 ("more stars than you can count").
How it differs from the plain verb and 〜てしまう
Against the plain verb, 〜きる is all about that added completeness: 食べる just says "eat," while 食べきる insists on "eat every last bit." Keep it off verbs that have no clear finish line, or it reads as strained.
Against 〜てしまう, the two overlap because both can translate as "finish" — but they emphasize different things:
- 〜きる stresses completeness — every last bit, to the end. Often positive: an achievement (走りきった = ran the whole way).
- 〜てしまう stresses completion as a done deal, often with regret or "oops" (食べてしまった = ate it / ended up eating it, possibly shouldn't have).
You can even combine them: 使いきってしまった ("I went and used it all up") layers both nuances. And remember it is a suffix on a stem, never a standalone verb — don't confuse it in plain text with the ordinary verb 切る ("to cut"), which takes its own object: 紙を切る ("cut the paper").
The short version
- ます-stem + きる = do the action completely / to the very end: 食べきる, 走りきる, 使いきる.
- Also marks a state taken to the extreme: 疲れきる, 困りきる.
- Conjugates as an う-verb: 〜きった, 〜きって; negative 〜きれない = "can't finish" / "too … to" (食べきれない, 覚えきれないほどの単語), never "can't cut."
- Emphasizes completeness; compare with 〜てしまう (completion, often regret).
Practice it
Choose the correct 〜きる / 〜きれない form for each sentence.
＿＿＿に入れるのに最もよいものを選びなさい。
量が多すぎて、この大盛りは一人では＿＿＿。
Frequently asked questions
What does 〜きる mean?
Attached to a verb's ます-stem, it means doing the action completely or all the way to the end: 食べきる ('eat it all up'), 走りきる ('run the whole way'). It can also mean reaching a state fully: 疲れきる ('be utterly exhausted').
What's the difference between 〜きる and 〜てしまう?
〜きる stresses completeness — every last bit, to the end, often a positive achievement. 〜てしまう stresses that something is done and over, often with regret. You can combine them: 使いきってしまった.
What does 〜きれない mean?
It's the potential-negative of 〜きる: 'cannot finish' or 'too … to.' 食べきれない = 'I can't finish eating it.' The set phrase 〜きれないほどの means 'more … than one can …': 数えきれないほどの星 ('countless stars').
Is 〜きる the same as the verb 切る ('to cut')?
It comes from 切る and conjugates the same way (〜きった, 〜きって), but as a stem suffix it means 'completely,' not 'cut.' The standalone verb 切る takes its own object: 紙を切る ('cut the paper').
Where 〜きる fits
Don't confuse it with
- 〜てしまう · N4 — 〜てしまう adds 'finish completely' or 'oops, ended up' to a verb. Learn the て-form formation, the regret nuance, past 〜てしまった, and the casual contractions 〜ちゃう / 〜じゃう.
- 〜かけ / 〜かける · N3 — 〜かけ attaches to a verb stem to mean an action is started but unfinished: 食べかけのパン (half-eaten bread), 読みかけの本 (book I'm partway through), 死にかけた (nearly died).
Once this clicks, go on to
- 〜一方だ · N3 — 〜一方だ marks a one-way, ongoing change that keeps intensifying — 物価は上がる一方だ ('prices keep rising'). Learn the form, the change-verb rule, and how it differs from 一方で.
More N3 grammar to explore
Keep going with related patterns at the same level:
- 〜っけ — 〜っけ is a casual sentence-final particle for confirming or recalling something half-forgotten: 明日は休みだっけ？ Learn how to attach it (だ/た + っけ) and when not to.
- 〜ことがある — Dictionary/ない-form verb + ことがある means 'sometimes' or 'there are times when' — an occasional event. Learn the formation, frequency adverbs, and how it differs from た-form ことがある (experience).
- 〜ことか — 〜ことか turns a question word into an exclamation of strong feeling: どんなに心配したことか ('how worried I was!'). Learn the formation, the rhetorical nuance, and common mistakes.
- 〜ことに — 〜ことに(は) fronts a sentence with the speaker's emotion: 驚いたことに ('to my surprise'), 残念なことに ('unfortunately'). Learn formation, the feeling-word rule, and placement.
- 〜くせに — 〜くせに means 'even though,' but always carries criticism or blame: 知っているくせに教えてくれない. Learn the formation, the same-subject rule, and how it differs from のに.
- めったに〜ない — めったに〜ない means 'rarely' or 'hardly ever.' Learn why it always pairs with a negative verb, how it compares to あまり〜ない, ほとんど〜ない, and 全然〜ない, plus examples.