How to tell them apart
ことができる explicitly states that an action is possible by nominalizing the verb, while られる fuses potentiality directly into the verb form. With ことができる you keep the dictionary verb intact and add ことができる, whereas られる changes the verb ending itself, e.g. 書くことができる vs 書ける. Swapping them is usually fine in meaning, but ことができる sounds more deliberate and formal, while られる is the everyday potential form. A key trap: られる requires conjugation by verb type, so する becomes できる and くる becomes こられる, whereas ことができる simply attaches to any dictionary-form verb.
- ことが出来る・できる Use ことができる when you want to clearly state that an action is possible, especially in formal or written contexts.
- られる Use られる when you want to express potential in everyday speech by conjugating the verb directly.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| ことが出来る・できる kotoga ru dekiru | To be capable of doing something; to have the ability | N4 |
| られる rareru | passive/potential form | N4 |
ことが出来る・できる kotoga ru dekiru
To be capable of doing something; to have the ability
ことが出来る・できる expresses ability or possibility, meaning that someone can do something. It attaches to a dictionary-form verb plus こと, as in 話すことが出来る, and できる can also stand alone in set phrases like できるだけ. It works in both polite and casual speech.
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何か私にできることがありましたらお知らせ下さい。
Let me know if there is anything I can do.
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父は英語を上手に話すことが出来る。
My father can speak English well.
られる rareru
passive/potential form
られる attaches to the mizenkei (negative stem) of verbs and creates either the passive, as in being eaten or built, or the potential, as in being able to go out or eat. Which reading applies depends on the sentence context.
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食べられることなくそのたこは、海に帰ったのであった。
That octopus returned to the sea without being eaten.
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来年ここに新しいホテルが建てられるだろう。
A new hotel will be built here next year.
ことが出来る・できる and られる are both JLPT N4 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.