ikeru-vs-ikukoto-ga-dekiru

If you have studied Japanese grammar, you have probably learned 〜ことができる (koto ga dekiru) as the standard way to say “can do something.” But native speakers use the potential form — like 行ける (ikeru) — far more often in everyday conversation. This guide explains exactly what the difference is and when to use each one.

Yuka

Rei, my teacher mentioned 行ける and 行くことができる today. What’s the difference?

Rei

Great question! Both come up a lot in everyday Japanese. The trick is knowing which context calls for which — let me show you!

At a Glance: 行ける vs. 行くことができる

The Potential Form: 行ける (ikeru)

In Japanese, every verb has a potential form that means “can [verb].” For 行く (iku, to go), the potential form is 行ける (ikeru). This is the natural, conversational way to express ability or possibility. Native speakers use the potential form constantly in daily speech.

Formation note: For う-verbs (Group 1), change the final う-row sound to the え-row + る. So 行く (iku) → 行ける (ikeru). For る-verbs (Group 2), remove る and add られる, though in casual speech this is often shortened to れる.

Example 1 — confirming availability:

明日のパーティーに行ける？
Ashita no paatii ni ikeru?
Can you make it to tomorrow’s party?

Example 2 — stating your own ability:

どこでも行けるよ。
Doko demo ikeru yo.
I can go anywhere.

Example 3 — polite form:

来週なら行けます。
Raishuu nara ikemasu.
I can go if it’s next week.

Yuka

I see… so context really matters with 行ける? It’s not just about the literal meaning?

Rei

Right! Japanese often works that way. 行ける especially has nuances that go beyond a direct translation — keep that in mind.

ことができる Form: 行くことができる (ikukoto ga dekiru)

〜ことができる is formed by taking the dictionary form of a verb, adding こと (which turns the verb into a noun — a process called nominalization), and then adding ができる (can do). It is grammatically equivalent to the potential form, but it sounds more formal and is more common in written Japanese, official documents, manuals, and formal speeches.

One additional use of ことができる: it can express permission (“you may do”) as well as ability, slightly more than the simple potential form.

Example 1 — formal written context:

このパスポートで日本に入国することができます。
Kono pasupooto de Nihon ni nyuukoku suru koto ga dekimasu.
You can enter Japan with this passport.

Example 2 — instruction manual / official notice:

このアプリで予約することができます。
Kono apuri de yoyaku suru koto ga dekimasu.
You can make reservations with this app.

Example 3 — formal speech:

皆様のおかげで、ここまで来ることができました。
Minasama no okage de, koko made kuru koto ga dekimashita.
Thanks to everyone, I was able to get this far.

Yuka

Got it. And 行くことができる — is that the opposite, or more like a different usage?

Rei

More of a different usage! 行くことができる carries its own feel. Comparing them together like this is actually the fastest way to master both.

This Pattern Applies to All Verbs

The choice between potential form and ことができる applies to every verb, not just 行く. Here are some parallel examples:

Decision Flowchart: Potential Form or ことができる?

Are you expressing ability or possibility?
        |
        v
Is the context FORMAL (document, speech, writing)?
   |                        |
  YES                       NO
   |                        |
   v                        v
ことができる              Potential form
sounds more natural       (e.g. 行ける, 書ける)
in formal/written         sounds most natural
Japanese                  in daily conversation

Quick Quiz — Test Yourself!

Yuka

I think I’ve finally got it! Let’s take the quiz to be sure.

Rei

Perfect confidence check! Let’s go — you’ve got this!

Choose the potential form or ことができる form. Think about whether the context is casual or formal.

Q1. (Casual) Hey, can you come to my place tomorrow?
ねえ、明日うちに＿＿＿？

Answer: 来られる？ or 来れる？(koreru?) — potential form; casual speech → potential form is natural. (来ることができる? is too stiff here.)

Q2. (Formal notice) Visitors can enter via the east entrance.
訪問者は東口から入館＿＿＿。

Answer: することができます (suru koto ga dekimasu) — formal notice → ことができる is appropriate.

Q3. (Casual) I can swim 1 km!
1キロ＿＿＿よ！

Answer: 泳げる (oyogeru) — casual boast → potential form is natural.

Q4. (Formal speech) Thanks to your support, I was able to complete this project.
皆さんのサポートのおかげで、このプロジェクトを完成＿＿＿ました。

Answer: させることができ (saseru koto ga deki) — formal speech context → ことができる fits naturally.

Q5. (Casual texting) Can you read Japanese?
日本語＿＿＿？

Answer: 読める？(yomeru?) — text message = casual → potential form.

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あわせて読みたい

Now that you understand potential forms, explore how 〜ようになる and 〜ようにする express ability and intent over time:

あわせて読みたい

〜ようになる vs 〜ようにする: \”It Came to Be\” vs \”I Make Sure To\” in ... Japanese learners often confuse ようになる (a change happened on its own) with ようにする (you're making a deliberate effort). This guide breaks down both forms with clear examples, a comparison table, and a decision flowchart so you always use the right one.

Also check out our guide on 〜みたいな vs. 〜ような — two ways to say “like” or “seems like” in Japanese:

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