“〜tara vs 〜to”: The Key Difference Between Two Conditionals [JLPT N4]

Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026

「帰ったら電話して」 vs 「押すと電気がつく」 — a request-friendly “if” vs an automatic result.

「〜たら」 vs 「〜と」 — whether volition/commands can follow is the key

「家に帰ったら、手を洗って」 (wash your hands once home) works, but 「家に帰ると、手を洗って」 doesn't — why? Both 「たら」 and 「と」 mark conditions, but the core difference: 「と」's latter clause can only be an “inevitable, natural result” — no volition, commands, or requests; 「たら」 has no such limit. This guide compares 「たら vs と」, clarifying this most error-prone point (the full comparison of the three conditionals has its own 〈conditionals overview〉 guide).

Core: と = inevitable/natural, たら = versatile (volition OK)

The core difference is whether the latter clause can be “volition, a command, or a request”:

• と = an inevitable, natural result (no volition after): 春になると、桜が咲く (come spring, cherry blossoms bloom — natural, inevitable). ✗ 春になると、花見しよう。
• たら = versatile (volition, commands, requests can follow): 春になったら、花見しよう (once spring comes, let's go blossom-viewing — an invitation follows).

Rule of thumb: latter is an “inevitable result” → either works; latter is “volition/command/request” → only たら.

How to Connect

實用例句

• 春になると、桜が咲く。(Come spring, cherry blossoms bloom.) — と (inevitable)
• このボタンを押すと、電気がつく。(Press this button and the light comes on.) — と (mechanical inevitability)
• 家に帰ったら、すぐ手を洗って。(Once home, wash your hands right away.) — たら (command)
• 日本に行ったら、寿司を食べたい。(If I go to Japan, I want to eat sushi.) — たら (volition)
• 気温が下がると、雪になる。(When the temperature drops, it turns to snow.) — と (natural)

⚠️ Common mistakes to avoid

① 「と」 can't be followed by commands, requests, volition, or invitations. ✗ 家に帰ると、電話して (call me once home — wrong, because “call” is a request). Use たら (家に帰ったら、電話して). This is the core, most-missed distinction of たら vs と.

② 「と」 marks an “inevitable, natural result.” Do the former and the latter (automatically, inevitably) happens — ボタンを押すと、開く (press and it opens), 春になると、暖かくなる. Mostly for natural phenomena, machine operation, general rules.

③ When unsure, use 「たら」. たら is versatile (hypothesis, completion, discovery all work; anything can follow). Only for “inevitable, natural cause-effect” (and the latter isn't volition) does と fit better. When hesitating, たら is safest.

🔄 Compare with similar forms: と／たら／ば

💡 Quick takeaway

For 「たら vs と」, one key is enough: whether “volition, a command, a request, or an invitation” follows. If it does → only たら (家に帰ったら電話して = call me once home, 日本に行ったら寿司食べよう = let's eat sushi in Japan); if not (an inevitable, natural result) → と or たら both work (春になると／なったら、桜が咲く). 「と」 is specifically for “as soon as… (inevitably, automatically)…” (ボタンを押すと開く, 春になると暖かい), where the latter is an objective result, not “I'll do／you do.” So if you see 「〜して (request), 〜しよう (invitation), 〜たい (wish)」 after, always use たら. For the full three-way comparison, see the 〈conditionals overview〉.

❓ Common questions

Q: How exactly do I tell 「たら」 from 「と」?

The key distinction: whether the latter clause can be “volition, a command, a request, or an invitation.” 「と」 can't — the latter can only be an “inevitable, naturally occurring result” (春になると桜が咲く = come spring, blossoms bloom; ボタンを押すと開く = press and it opens). 「たら」 can — commands, requests, volition, wishes all follow (家に帰ったら、電話して = call me once home). So “call after getting home (a request)” must use たら, not と. Test: latter is “an action I/you will do” → たら; latter is “an automatically occurring result” → と (or たら).

Q: When must I use 「と」 and not 「たら」?

Strictly, たら can almost always replace と (for hypothesis/condition). But 「と」 fits best and is most common for “repeated, inevitable natural laws”: ① natural phenomena (春になると暖かくなる = come spring it warms up); ② the inevitable result of a machine/operation (このボタンを押すと、ドアが開く = press this button and the door opens); ③ general rules/habits (お酒を飲むと、顔が赤くなる = drinking makes my face red). For these “as soon as… (inevitably)…” cases, と is most natural (たら works too, but loses that “inevitable, law-like” feel).

🖊️ Practice Questions (5)

Q1. 「家に帰っ___、すぐ手を洗ってね。」(please wash your hands right after you get home)

(A) たら　(B) と　(C) ば　(D) なら

Q2. 「気温が下がる___、雪になる。」(when the temperature drops, it snows — natural inevitability)

(A) と　(B) たら　(C) ても　(D) のに

Q3. 「と」が使えないのはどれか?

(A) ボタンを押すと、止めてください(followed by a request)

(B) 春になると、暖かくなる

(C) 右に曲がると、駅がある

(D) 2に3を足すと、5になる

Q4. 「たら」と「と」の違いとして正しいのは?

(A) たら can be followed by volition / command / request; と only takes an inevitable result

(B) The two are exactly the same

(C) と can be followed by a command

(D) たら is used only for natural phenomena

Q5. 自然・機械的必然結果として「と」が自然なのは?

(A) 水は0度になると凍る。　(B) 駅に着くと電話して。

(C) 暇だと遊びに行こう。　(D) 安いと買ってください。

Answer Explanations

1. (A) たら ── Followed by a request (wash hands), so use たら.

2. (A) と ── Temperature drops → it snows (natural inevitability).

3. (A) ── と is not followed by a request, so (A) doesn't work (should use たら).

4. (A) ── たら can take volition/command; と only takes inevitability.

5. (A) ── 「0度になると凍る」is natural inevitability; (B)(C)(D) are followed by commands/volition and should use たら.