Japanese conditionals: ば, たら, と and なら, explained

All four put the condition first and the result second: 押すと開く, "press it and it opens". English uses "if" or "when" for all of them, so the English sentence rarely tells you which one to pick. What decides it is the second half of the sentence: whether it is a fact or something you want, whether it is about the past, and whether it happens before or after the condition. The first table shows how each form attaches; the second, what each allows.

Most people meet the four through mottos: と is "natural consequence", ば is "hypothetical", たら is "one-time events", なら is "contextual". The first is right, the rest are half-truths. ば does not express inevitability (that is と), and たら works perfectly well for repeated and general events: 春になったら、暖かくなる is as natural as 春になると. The procedure below asks about the second half of the sentence instead, which is where the four really differ. Go through it in order and stop at the first yes.

• 1. Is the second half advice or a reaction to something the listener just said, or does it happen before the condition does? Use なら.
• 2. Is the second half a request, a command, an invitation, a suggestion or your own plan? Use たら. ば works too, but only if the condition is a state (ある, いる, できる, an adjective, a negative). と never does.
• 3. Is it a real past event, "when I did X, Y happened" or "I found Y"? Use たら, or と in written narrative. Not ば, not なら.
• 4. Is the result automatic, habitual or a fixed fact: a machine, nature, directions, a routine? Use と. ば and たら are also possible; と is the most typical.
• 5. Are you stressing the condition itself: "provided that", "as long as", "what should I do"? Use ば.
• 6. Still unsure? Use たら. In conversation it is the widest of the four and the least likely to be wrong.

と attaches to the plain non-past form: 押すと, 食べると, 高いと, and with nouns and な-adjectives through だ: 学生だと, 静かだと. It says that whenever the first thing happens, the second follows as a matter of course. That makes it the conditional of machines and switches, nature, directions, habits and facts about the world: "press this and it opens", "spring comes and the cherries bloom", "go straight on and the station is on your right". The English is "when", "whenever" or "if", and the Japanese sentence feels like a description rather than a hypothesis.

Because the result is presented as automatic, the second half must be a statement of fact. It cannot be what the speaker wants: no request (〜てください), no command, no invitation (〜ましょう), no intention (〜つもり, 〜たい), no suggestion and no permission. 駅に着くと、電話してください is the classic error; the request needs たら: 駅に着いたら、電話してください. The と clause itself stays in the non-past even when the story is in the past. There is no 押したと as a conditional.

Break down your own sentence

In written narrative と also links two past events, with the second one something that happened or that the character noticed: ドアを開けると、猫がいた, "I opened the door and there was a cat". The main clause is in the past, the と clause still in the non-past. This is the storytelling use; in conversation the same sentence would usually take たら (ドアを開けたら、猫がいた).

Two lookalikes are worth separating. A clause before 言う, 思う or 聞く ends in the quotative と, not the conditional: 行くと言った is "said he would go". And 〜ないと on its own is short for 〜ないといけない, "must": 早く行かないと, "I have to go soon". Both look like a conditional and neither is one in meaning.

• この道をまっすぐ行くと、右に郵便局があります。Go straight along this road and there is a post office on the right. (directions)
• 冬になると、この湖は凍ります。When winter comes, this lake freezes. (nature)
• 父は家に帰ると、まずお風呂に入る。When my father gets home, the first thing he does is have a bath. (habit)
• 箱を開けると、手紙が入っていた。I opened the box, and there was a letter inside. (written narrative)

ば is formed from the verb itself: the final -u becomes -e and ば is added. 行く becomes 行けば, 待つ becomes 待てば, 食べる becomes 食べれば, する becomes すれば, 来る becomes 来れば (くれば). An い-adjective swaps its い for ければ: 高い, 高ければ; いい is irregular, よければ; ない gives なければ, so the negative of any verb is 〜なければ (行かなければ). Nouns and な-adjectives have no ば-form of their own. The copula's is なら(ば), so 学生なら is in origin the ば-form of 学生だ; in formal Japanese you also see 学生であれば and 静かであれば.

ば puts the weight on the condition: the result holds if, and as long as, the condition is met. "Provided that" and "as long as" are often closer to it than "if". That is why ば is the form of general rules, proverbs and advice: 練習すれば上手になる ("practise and you will get better"), 塵も積もれば山となる ("even dust, piled up, becomes a mountain"), and the question every learner needs, どうすればいいですか, "what should I do?". 〜ばいい is "all you need to do is…", and 〜ばよかった is regret, "I should have…": もっと早く寝ればよかった.

The restriction on ば depends on the condition, not on ば itself. When the ば clause is an action (行く, 食べる, 着く, 終わる), the second half cannot be the speaker's request, command, invitation or intention: 東京に行けば、連絡してください sounds wrong, and the request needs たら. When the ば clause is a state, the second half is free. States are ある and いる, できる and other potentials, わかる, adjectives, and any negative: 時間があれば、手伝ってください; 安ければ、買います; 天気がよければ、海に行きましょう. Usage varies at the edges. When the two halves have different subjects, many speakers accept an action before an intention (あなたが行けば、私も行きます), and in casual speech you will hear more than textbooks allow.

ば does not report what actually happened. ドアを開ければ、猫がいた is not Japanese for "when I opened the door, there was a cat"; that needs たら or と. A past main clause after ば is either a habit (若い頃は、時間があれば本を読んだ, "when I was young I read whenever I had time") or a counterfactual: もう少し早く出れば間に合ったのに, "if I had left a bit earlier I would have made it".

• 駅までどう行けばいいですか。How should I get to the station? (〜ばいい, asking for advice)
• 分からなければ、聞いてください。If you don't understand, please ask. (negative condition, so a request is fine)
• 練習すればするほど、上手になる。The more you practise, the better you get. (〜ば〜ほど)
• 傘を持ってくればよかった。I should have brought an umbrella. (〜ばよかった, regret)

Explain ば, たら, と and なら at your levelwith Plus

たら is the plain past plus ら: 行った, 行ったら; 食べた, 食べたら; 高かった, 高かったら; よかった, よかったら; 学生だった, 学生だったら. The negative is 〜なかったら. Because it is built on the past, it carries the idea of completion: the condition is finished first, and the result comes after. That one idea covers its two everyday meanings. As a hypothesis it is "if": もし雨が降ったら、試合は中止です, "if it rains, the match is off". With something certain to happen, it is "when" or "once": 家に着いたら、連絡するね, "I'll message you once I get home"; 二十歳になったら, "when I turn twenty".

たら puts no limit on the second half. Requests, commands, invitations, intentions and suggestions all follow it freely, whatever the condition is: 終わったら、教えてください; 着いたら、電話して; 時間ができたら、飲みに行こう. That is the gap ば and と leave, and it is why たら is the default in conversation. Two set uses are worth knowing: 〜たらどう？ is a suggestion, "why don't you…?" (先生に聞いたらどう？), and 〜たらいい asks or gives advice much like 〜ばいい. In formal writing, reports and rules, ば and と are preferred, and たら can sound chatty.

With a past main clause, たら takes on a third meaning: "when I did X, I found Y" or "when I did X, Y happened". The second half is something the speaker discovered or did not control. This is the conversational version of narrative と.

The limit of the discovery use is the speaker's own will. 家に帰ったら、母がケーキを作っていた ("when I got home, Mum was baking a cake") is natural, because the cake is what the speaker found. 家に帰ったら、宿題をした is not, because doing homework is the speaker's own next step, not a discovery. For a plain sequence of your own actions, use the te-form or 〜てから: 家に帰って、宿題をした.

• 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? (hypothesis; もし strengthens the "if")
• 仕事が終わったら、飲みに行かない？Fancy a drink once work is over? (invitation after たら)
• ホテルに着いたら、電話してください。Please phone me when you get to the hotel. (request after たら)
• 駅に行ったら、もう電車は出ていた。When I got to the station, the train had already left. (discovery)

なら attaches to plain forms, and straight to nouns and な-adjectives with no だ: 行くなら, 行ったなら, 高いなら, 静かなら, 学生なら. The fuller ならば is formal, and 行くのなら or 行くんなら adds emphasis to the premise. なら does not describe a condition that brings about a result. It takes something up, whether something the listener has just said, a topic, or a supposition, and says what follows given that. "If that is the case", "if it is X you mean", "if you are going to…".

Its home is advice and reaction. 「来週京都に行くんです。」「京都に行くなら、金閣寺を見てください。」: the listener mentions a trip and the speaker builds on it. With a noun it picks out a topic: 寿司なら、駅前の店がおいしいよ, "if it is sushi you want, the place by the station is good". Because it only takes the condition up as a premise, なら sets no time order. The result can come before the event in the condition. なら is wrong where the others are at home, for automatic results (春になるなら、桜が咲く) and for real past events.

The pair below is where たら and なら part. The words are identical except for the conditional ending, and the coat is bought at a different time.

Translated loosely, both are "if I go to Hokkaido, I'll buy a coat", and that is why learners mix them up. The order of events is the test. If the result has to happen first, as with preparation, advice before a trip or a recommendation, only なら works: 日本に行くなら、円に両替しておいたほうがいい, "if you're going to Japan, change some money into yen first". If the result comes after the condition is complete, たら is the form, and なら would turn the sentence into a comment on a premise.

なら after a past form is a different use again: 本当に行ったなら、写真を見せて, "if you really went, show me the photos". The going is taken as a claim to be accepted or checked, not as an event to wait for. たら cannot do this: 行ったら would mean "once you have gone".

• 日本語なら、少し話せます。As for Japanese, I can speak a little. (なら picking out a topic)
• 眠いなら、もう寝たら？If you're sleepy, why not go to bed? (なら taking up what the listener shows; 〜たら as a suggestion)
• パソコンを買うなら、軽いのがいいですよ。If you're buying a laptop, a light one is best. (advice before the purchase)
• パソコンを買ったら、まずバックアップを設定してください。Once you have bought a computer, set up backups first. (after the purchase)

• Not駅に着くと、電話してください。

  But駅に着いたら、電話してください。

  と presents the result as automatic, so the second half must be a fact. A request, command, invitation or intention needs たら.

• Not東京に行けば、連絡してください。

  But東京に行ったら、連絡してください。

  When the ば clause is an action verb, the main clause cannot be a request or intention. ば is fine before a request only after a state: 時間があれば、連絡してください.

• Notドアを開ければ、猫がいた。

  Butドアを開けたら、猫がいた。

  ば does not report a real past event. "When I did X, I found Y" is たら, or と in narrative.

• Not家に帰ったら、宿題をした。

  But家に帰って、宿題をした。

  With a past main clause, たら introduces something you found or something that happened to you, not your own next deliberate step. A plain sequence of your own actions takes the te-form or 〜てから.

• Not（出発前の助言）ドイツに行ったら、ドイツ語を少し勉強したほうがいいよ。

  Butドイツに行くなら、ドイツ語を少し勉強したほうがいいよ。

  たら puts the trip first, so the advice would be to study once already in Germany. Advice about what to do before the event takes なら, which sets no time order.

• Not学生だなら、割引があります。

  But学生なら、割引があります。

  なら attaches straight to nouns and な-adjectives; the だ drops. 学生だったら is also right; 学生だなら is not a form.

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Epsylo's breakdowns usually keep a conditional attached to its verb, as one word such as 行ったら or よければ, with a gloss like "if (it) is good" and a word card that names the form. なら often stands as a word of its own. The breakdowns on this page split the ending off so that you can look at it alone. Paste a sentence from a message, a sign or a manual and check which conditional it uses and what follows it.

Break down a Japanese sentence

What is the difference between ば and たら?

ば stresses the condition, "provided that", and is common in general statements and advice (どうすればいいですか). たら stresses completion, "once X has happened", and is freer: it can be followed by a request or intention whatever the condition is, and it can describe a real past discovery (窓を開けたら、雪が降っていた). ば can do neither with an action verb. In many everyday sentences either works.

Can I use と before ください?

No. と presents the second half as an automatic consequence, so it cannot be a request, command, invitation or intention. 駅に着くと、電話してください is wrong; say 駅に着いたら、電話してください.

When should I use なら instead of たら?

When you are taking up something the listener said or a topic (寿司なら…), when you are giving advice based on a premise, and whenever the result has to happen before the condition: 北海道に行くなら、コートを買います means buying the coat before the trip. たら always puts the condition first.

Which Japanese conditional should I use if I am not sure?

たら. In conversation it is the widest of the four: it takes requests, invitations and intentions, works for one-off and repeated events, and covers past discoveries. Switch to なら for advice and preparation before an event, and to と for automatic results in instructions and directions.

What does 〜ばよかった mean?

Regret about the past: "I should have…", "if only I had…". 傘を持ってくればよかった is "I should have brought an umbrella". 〜たらよかった means the same and is more conversational.

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