N4 · Conditions
たら: if and when, the all-purpose conditional
the conditional たら
The plain past plus ら: once A has happened, B.
Take the plain past form and add ら: 行った becomes 行ったら, 高かった becomes 高かったら, 雨だった becomes 雨だったら. If you can make the past, you can make たら; every irregularity it has is an irregularity of the past tense.
The た does not mean past here. It means "completed": B comes after A is finished. 明日雨が降ったら is about tomorrow, and says "if it rains — once that has happened". English speakers see the た and hesitate to use it for the future; that hesitation is the main thing to unlearn.
たら covers both "if" and "when". If A may or may not happen, it is "if": もし宝くじが当たったら. If A is certain, it is "when" or "as soon as": 十時になったら、出かけましょう. Adding もし at the start makes the "if" reading explicit.
It is the most flexible of the four conditionals. The second half can be a request, an invitation, a wish or a plan, which と and often ば do not allow. That makes たら the safe choice in conversation — the one exception is advice about what to do before A, which needs なら.
The form
stem (regular) stem (irregular) ending
| 書く, to write | 書いたら |
| 読む, to read | 読んだら |
| 食べる, to eat | 食べたら |
| 行く, to go | 行ったら |
| する, to do | したら |
| 来る, to come | 来たら |
| 高い, expensive | 高かったら |
| 静か, quiet | 静かだったら |
| 行かない, not go | 行かなかったら |
| noun: if it is rain | 雨だったら |
The rules one by one
Make the plain past and add ら.
仕事が終わったら、飲みに行きましょう。When work is over, let's go for a drink.
A is finished before B begins, whatever the tense of the sentence.
家に着いたら、メッセージを送ります。I will send a message when I get home.
The second half can be a request, an invitation, a wish or a plan.
分かったら、手を挙げてください。If you understand, please raise your hand.
もし at the start makes it clearly hypothetical.
もし宝くじが当たったら、何を買いますか。If you won the lottery, what would you buy?
With a past-tense ending, たら tells what you found when you did A.
箱を開けたら、手紙が入っていました。When I opened the box, there was a letter inside.
A closer look
Why the past tense can talk about tomorrow
The Japanese た was once a marker of completion rather than of time, and inside a conditional it still is. 明日着いたら places you in tomorrow, at the moment just after arriving, and looks forward from there.
English does something similar without noticing: "when you have finished, come and see me" uses a perfect for a future event. The Japanese form is the same idea made regular — and it is why たら cannot be used when B has to happen before A.
Exceptions and special cases (1)
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the verb is 行く
the form is 行ったら, with a small っ, not いいたら.
東京に行ったら、連絡します。I will get in touch when I go to Tokyo.
行く is the one godan verb in く whose past is 行った rather than いいた, and たら inherits the irregular past.
How to spot it
- 〜たら
- 〜だら
- 〜かったら
- 〜だったら
- もし〜たら
- 〜たらどうですか
Example sentences
駅に着いたら、電話してください。Please call me when you get to the station.
もし雨が降ったら、試合は来週になります。If it rains, the match will be next week.
大人になったら、医者になりたいです。When I grow up, I want to be a doctor.
安かったら、二つ買います。If they are cheap, I will buy two.
暇だったら、一緒に映画を見ませんか。If you are free, would you like to watch a film together?
家に帰ったら、荷物が届いていました。When I got home, the parcel had arrived.
7 more example sentences
十時になったら、出かけましょう。Let's leave when it gets to ten.
寒かったら、エアコンをつけてもいいですよ。If you are cold, you can turn on the air conditioning.
今出たら、間に合うかもしれません。If we leave now, we might make it.
薬を飲んだら、少し楽になりました。After I took the medicine, I felt a little better.
もし明日休みだったら、どこに行きたいですか。If you had tomorrow off, where would you like to go?
駅を出たら、雨が止んでいました。When I came out of the station, the rain had stopped.
先生に聞いたら、教えてくれました。When I asked the teacher, she explained it to me.
Worth knowing (1)
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たらどうですか: a suggestion
〜たらどうですか, "how would it be if you…", is a polite suggestion. Among friends it shortens to 〜たら？ with a rising voice. Used to somebody senior it can sound pushy, so keep it for equals and juniors.
少し休んだらどうですか。Why not take a short break?
The trap English speakers fall into
Watch out
Because the sentence is about the future, it is tempting to attach たら to the dictionary form. But たら is built on the past form, always: the た marks that A is complete, not that it lies in the past. 終わったら means "once it is finished".
たら means once A is done, then B — and B can be anything.
Your turn
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