How to Use the Japanese Conditional たら | “If” and “When” Grammar

level2 (N4)
How to Use the Japanese Conditional たら | “If” and “When” Grammar
Source: gokigen japanese official YouTube Channel

Introduction

Want to say “If…” or “When…” in Japanese?
Then it’s time to learn the たら-form:

👉 V / adj (short past) + ら

This grammar lets you express conditional situations or what happens after a certain event.
Let’s look at how it works!


1. Meaning

💡 Pattern: V / adj (short past) + ら, 〜 = If / When 〜

This pattern is used for:

  • Conditions: “If it rains, I won’t go.”
  • Sequences: “When I get home, I’ll call you.”
  • Hypotheticals: “If I were a cat, I’d sleep all day.”

In an A たら B sentence, A has to occur before B. Or to put it another way, A has to occur in order for B to occur and B will always occur after A.

gokigen penguin
gokigen penguin

A たら B implies that B is true provided A is true / happens. Depending on context, this could be translated as ‘if A then B’, or ‘when A, then B’.


2. How to Form the たら Form

  • Step1: Take the short past form of a verb or adjective
  • Step2: add

Affirmative

Base FormShort Pastたら-form
く (to go)行った行ったら
する (to do)したしたら
雨だ (it’s rainy)雨だった雨だったら
たかい (expensive)高かった高かったら

Negative

Base FormShort Pastたら-form
かない (not to go)行かなかった行かなかったら
しない (not to do)しなかったしなかったら
あめじゃない (it’s not rainy)雨じゃなかった雨じゃなかったら
たかくない (not expensive)高くなかった高くなかったら

If you need a refresher on plain past tense conjugation, see these articles.


3. Example Sentences

Hypotheticals

  • わたしとりだったらそらびたいです。
    → If I were a bird, I’d want to fly in the sky.
  • わたしねこだったら一日中いちにちじゅう ているでしょう。
    → I would sleep all day if I were a cat.

Conditions

  • あつかったら、ネクタイをしません。
    → If it’s hot, I won’t wear a tie.
  • たかくなかったら、そのくついます。
    → If it’s not expensive, I’ll buy those shoes.
  • あめらなかったら公園こうえんきます。
    → If it doesn’t rain, I’ll go to the park.

Sequences

  • 授業じゅぎょうわったら電話でんわします。
    → I’ll call you when class ends.
  • 宿題しゅくだいわったらあそびましょう。
    → Let’s play once we finish the homework.
  • 学校がっこうったら先生せんせいいました。
    → When I went to school, I met the teacher.

4. Practice Time!

Talk about what you would do in the following situations, using たら.

SituationAnswer
ともだちがいえる / おちゃをいれる友だちが家にたら、お茶をいれます。
→ If my friends come over, I’ll make some tea.
ショッピングモールにく / シャツをいたいショッピングモールに行ったら、シャツを買いたいです。
→ If I go to the shopping mall, I want to buy a shirt.
たかくない / そのかばんを高くなかったら、そのかばんを買います。
→ If it’s not expensive, I’ll buy that bag.
あつい / ネクタイをしない暑かったら、ネクタイをしません。
→ If it’s hot, I won’t wear a tie.
たからくじにたる / くるまいたい宝くじに当たったら、車を買いたいです。
→ If I win the lottery, I want to buy a car.
日本語にほんご上手じょうずになる / 日本語のマンガをみたい日本語が上手になったら、日本語のマンガを読みたいです。
→ If I become good at Japanese, I want to read Japanese manga.

🎯 Try 2 more with your own ideas!


5. Common Mistakes

  • Using dictionary form instead of short past
    → × 宿題が終わったら → ✅ OK
    → × 宿題が終わるら → ❌ NG
  • Using たら for reversed sequence
    → × 「スピーチがあったら、練習したほうがいい」
    → ✅ Use なら instead, because B happens before A

6. Advanced Note: たら vs なら

  • AたらB = A happens first, then B happens
  • AならB = If A is true, then B applies

⛔ So don’t use たら if B happens before A!

Example: If you have a speech presentation next week, you should practice.

  • Wrong: 来週らいしゅうスピーチがあったら練習れんしゅうしたほうがいい。
  • Correct: 来週スピーチがあるなら、練習したほうがいい。
gokigen penguin
gokigen penguin

In this example, the order of actions is: first you practice (B), and then you have a speech (A).
たら cannot be used for this sentence, because B (you practice) happens before A (have a speech).


7. FAQ – Frequently Asked Questions

Q
How is 〜たら different from other “if” conditionals like 〜と (to) and 〜ば (ba)?
A
  • 〜たら: Implies a definite completion of the preceding action/condition before the consequence. It’s versatile for both specific, one-time conditions (“If/When I arrive…”) and hypothetical situations.
  • 〜と: Implies an automatic or natural result every time the condition is met (“When/If you turn the key, the car starts”). It’s often used for universal truths or regular occurrences.
    Example: そのくすりむと、元気げんきになりますよ。= If you take that medicine, you’ll feel better.
  • 〜ば (ba): Often expresses a general condition or a suggestion (“If you study, you’ll pass”). It can sound slightly more formal or academic than 〜たら in some contexts.
    Example: その薬を飲めば、元気になりますよ。= If you take that medicine, you’ll feel better.
Q
Can I use 〜たら for things that didn’t happen (counterfactuals) or for wishes?
A

Yes, 〜たら is commonly used for counterfactuals (things that didn’t happen) or to express wishes for something different, especially when combined with expressions like 〜よかった (yokatta – “it would have been good if…”) or 〜のに (noni – “even though/despite”).

  • もし時間があったら、もっと勉強したかった。 (Moshi jikan ga attara, motto benkyō shitakatta.) – “If I had had time, I would have wanted to study more.”
  • 雨が降らなかったらよかったのに。 (Ame ga furanakattara yokatta noni.) – “I wish it hadn’t rained (but it did).”
Q
Can 〜たら be used for requests or commands in the result clause?
A

Yes, absolutely! 〜たら is very commonly used when the result clause is a request, suggestion, command, or prohibition.

  • Example (request): もし時間がなかったら、連絡してください。 (Moshi jikan ga nakattara, renraku shite kudasai.) – “If you don’t have time, please contact me.”
  • Example (suggestion): 疲れたら、休んだほうがいいですよ。 (Tsukaretara, yasunda hō ga ii desu yo.) – “If you’re tired, you should rest.”
  • Example (command): そこに行ったら、これを渡して。 (Soko ni ittara, kore o watashite.) – “When you go there, hand this over.”

Conclusion

Now you can:

✅ Use 〜たら to express conditions and sequences
✅ Conjugate verbs and adjectives into たら-form
✅ Create natural “if/when” sentences in Japanese!

🎯 Challenge: What would you do if you won the lottery? Try answering in Japanese with 〜たら!

Want to improve your Japanese with real conversations?

Our native Japanese instructors at gokigen japanese can help you perfect your pronunciation and learn real-life usage.

Whether you’re completely new to Japanese or looking to refine your skills, book a one-on-one session.


Author

  • gokigen japanese

    gokigen japanese is an online Japanese tutoring service launched in 2023. Flexible, interactive, and culture-rich, gokigen japanese supports learners at all levels with bilingual Japanese tutors.
    Over 1,000 students from 30+ countries have used our 300+ original materials, including grammar guides and cultural content.

    gokigen japanese was founded by Hirofumi Naramura, a Kyoto University graduate and former Project Leader at the Boston Consulting Group (2010–2020). The service has received recognition such as the Chiyoda CULTURE x TECH Award 2024 and acceptance into NEXs Tokyo, a startup program by the Tokyo Metropolitan Government.