The One That Does Everything
Japanese has four conditionals — ば, と, たら and なら — and たら is the one you can lean on. If you are unsure which to use, たら is almost always acceptable.
Our lesson on conditionals compares all four side by side.
How to Form It
Make the た form and add ら. Nothing else changes.
| Type | Plain past | + ら |
|---|---|---|
| Verb | 行った | 行ったら |
| い-adjective | 安かった | 安かったら |
| な-adjective | 暇だった | 暇だったら |
| Noun | 雨だった | 雨だったら |
Because the た form is easy, so is this — no group rules, no exceptions.
Two Meanings: "If" and "When"
たら covers both, and context decides which:
- お金があったら買います。(If I had the money, I'd buy it.) — uncertain
- 駅に着いたら電話します。(When I arrive, I'll call.) — certain
If the first clause will definitely happen, たら reads as "when."
What Makes たら Different
The other conditionals restrict what can follow them. たら does not:
| Conditional | Can the second clause be a request or command? |
|---|---|
| たら | yes |
| ば | limited |
| と | no — only automatic results |
| なら | yes, but the topic must already be raised |
- ○ 時間があったら手伝ってください。
- × 時間があると手伝ってください。
That freedom is why たら is the safe default.
The Discovery Use
With a past-tense second clause, たら stops meaning "if" and reports a surprise:
- 家に帰ったら、誰もいなかった。(When I got home, nobody was there.)
Nothing is conditional here — it describes what you found on doing something.
たらどうですか — Making a Suggestion
- 医者に行ったらどうですか。(Why don't you see a doctor?)
Casually this shortens to 〜たら？ with rising intonation.