Tara Conditional in Japanese

In Brief

The Japanese たら conditional expresses “if,” “when,” or “after”: Xたら、Y means that Y happens if or once X becomes true. Form it by adding ら to the plain past form: 行った → 行ったら, 安かった → 安かったら, 静かだった → 静かだったら. Although it contains a past-looking form, the whole condition can refer to the future.

Overview

The たら conditional (たら条件) joins a condition to its result. A condition is simply the part that sets the circumstances: “if it rains,” “when work finishes,” or “if the room is quiet.” In the usual Japanese order, the condition comes first:

Xたら、Y。
If/when X, Y.

This is an important A2 pattern because it works in many everyday situations. You can use it for uncertain possibilities, expected future events, advice, requests, intentions, and sequences in which one event must finish before another begins. English divides these meanings among if, when, and after; Japanese often uses the same たら form and lets context show the best translation.

The beginner rule is straightforward: make the plain past form—the た-form, meaning the form ending in た or だ—and add ら. The most important idea is not past time but a condition reached before the result. In 日本に行ったら、富士山に登りたいです, the trip to Japan is still in the future: “When I go to Japan, I want to climb Mt. Fuji.”

How It Works

The basic pattern

A sentence with たら has two clauses (parts of a sentence that each describe an event or state):

condition + たら、result

• 雨が降ったら — if it rains
• 家にいます — I will stay home
• 雨が降ったら、家にいます。 — If it rains, I’ll stay home.

The first clause sets the condition. The second gives the result, decision, request, discovery, or next action.

Verbs: add ら to the た-form

Use the verb’s plain た-form and add ら. The ending may be た or だ, depending on the verb, but the added element is always ら.

Dictionary form	た-form	たら form	Meaning
食べる	食べた	食べたら	if/when (someone) eats
行く	行った	行ったら	if/when (someone) goes
読む	読んだ	読んだら	if/when (someone) reads
話す	話した	話したら	if/when (someone) speaks
する	した	したら	if/when (someone) does
来る	来た	来たら	if/when (someone) comes

If you already know the た-form, there is no new verb-conjugation pattern to memorize. Keep the complete た-form and attach ら: 読んだ + ら = 読んだら, not 読んたら.

い-adjectives

An い-adjective is an adjective whose basic form normally ends in い, such as 安い “cheap” or 寒い “cold.” Change final い to かった, then add ら.

Basic form	Plain past	たら form	Meaning
安い	安かった	安かったら	if it is cheap
忙しい	忙しかった	忙しかったら	if you are busy
寒い	寒かった	寒かったら	if it is cold
いい	よかった	よかったら	if it is good / if you like

Notice the irregular-looking change いい → よかったら. The word いい uses よ- in forms such as よかった and よくない.

な-adjectives and nouns

A な-adjective is an adjective that uses な before a noun, such as 静かな部屋 “a quiet room.” For a positive たら condition, な-adjectives and nouns (words for people, things, places, or ideas) use だったら.

Type	Basic expression	たら form	Meaning
な-adjective	静かだ	静かだったら	if it is quiet
な-adjective	暇だ	暇だったら	if (someone) is free
noun	学生だ	学生だったら	if (someone) is a student
noun	日曜日だ	日曜日だったら	if it is Sunday

In polite conversation, でしたら is a more formal alternative: ご都合がよろしいようでしたら and similar expressions occur in careful service or business language. For ordinary conversation, plain だったら inside an otherwise polite sentence is completely normal: 暇だったら、手伝ってください。

Negative conditions

To say “if not,” make the plain negative past form ending in なかった, then add ら. For nouns and な-adjectives, use ではなかったら or the conversational じゃなかったら.

Type	Negative たら form	Meaning
verb	行かなかったら	if (someone) does not go
い-adjective	高くなかったら	if it is not expensive
な-adjective	静かじゃなかったら	if it is not quiet
noun	学生じゃなかったら	if (someone) is not a student

The result clause may itself be negative: 雨が降ったら、行きません means “If it rains, I won’t go.” Do not confuse this with 雨が降らなかったら、行きます: “If it doesn’t rain, I’ll go.”

Future meaning despite the past form

English normally says “if it rains,” not “if it rained,” when discussing a real future possibility. Japanese nevertheless uses 降ったら. The た in たら marks the condition as completed or established before the result; it does not force the whole sentence into past time.

• 明日、晴れたら、散歩しましょう。 — If it is sunny tomorrow, let’s take a walk.
• 駅に着いたら、電話してください。 — Call me when you arrive at the station.

Time words such as 明日 “tomorrow” and the context make the time reference clear.

Examples in Context

Japanese	English	Note
雨が降ったら、家にいます。	If it rains, I’ll stay home.	An uncertain future condition
安かったら買います。	I’ll buy it if it’s cheap.	い-adjective condition
日本に行ったら、富士山に登りたいです。	When I go to Japan, I want to climb Mt. Fuji.	A future plan after another event
終わったら教えてください。	Please tell me when you’re finished.	Request in the result clause
駅に着いたら、メッセージを送ってね。	Send me a message when you get to the station.	Casual request; ね softens it
時間があったら、一緒に昼ご飯を食べませんか。	If you have time, would you like to have lunch together?	Invitation based on a condition
この部屋が静かだったら、ここで勉強します。	If this room is quiet, I’ll study here.	な-adjective with だったら
明日が休みだったら、映画を見に行きます。	If tomorrow is a day off, I’ll go see a movie.	Noun condition with だったら
高くなかったら、そのホテルを予約しましょう。	If it isn’t expensive, let’s book that hotel.	Negative い-adjective condition
田中さんが来なかったら、先に始めましょう。	If Tanaka doesn’t come, let’s start without him.	Negative verb condition
春になったら、庭に花を植えます。	When spring comes, I’ll plant flowers in the garden.	Expected future time
宿題をしたら、ゲームをしてもいいです。	After you do your homework, you may play games.	One action must precede another
ドアを開けたら、猫がいました。	When I opened the door, there was a cat.	Past discovery
よかったら、これを使ってください。	If you like, please use this.	Common polite offer

The English translation changes with the situation. 着いたら is naturally “when you arrive” if arrival is expected, while 雨が降ったら is often “if it rains” because rain is uncertain. 宿題をしたら may be best rendered “after you do your homework” because completion must come first.

Common Mistakes

Adding ら directly to the dictionary form

• Wrong: 日本に行くら、京都も見たいです。
• Right: 日本に行ったら、京都も見たいです。
• Why: たら attaches to the た-form, not directly to 行く. First make 行った, then add ら.

Losing だ in a verb’s た-form

• Wrong: 本を読んたら、返してください。
• Right: 本を読んだら、返してください。
• Why: The た-form of 読む is 読んだ. Keep that entire form before adding ら.

Treating all adjectives alike

• Wrong: 安いだったら、買います。
• Right: 安かったら、買います。
• Why: い-adjectives use -かったら. だったら belongs to nouns and な-adjectives: 便利だったら, 日曜日だったら.

Using な before だったら

• Wrong: 静かなだったら、ここで寝ます。
• Right: 静かだったら、ここで寝ます。
• Why: な appears before a noun, as in 静かな部屋. Before だったら, use the adjective stem: 静かだったら.

Reading たら as past tense every time

• Misleading interpretation: 明日雨が降ったら = “if it rained tomorrow”
• Natural interpretation: 明日雨が降ったら、家にいます。 = “If it rains tomorrow, I’ll stay home.”
• Why: The form is built from the plain past, but a たら condition can refer to the future. Read the whole sentence and look for time expressions.

Reversing the real-world sequence

• Unnatural for the intended meaning: 家を出たら、朝ご飯を食べます。 when you mean that breakfast comes first
• Right: 朝ご飯を食べたら、家を出ます。 — After I eat breakfast, I’ll leave home.
• Why: In sequential uses, the event before たら must occur before the event in the result clause.

Usage Notes

“If,” “when,” and “after” are contextual translations

Japanese does not require you to choose among three separate words here. Translate according to certainty and sequence:

• if for an open possibility: 雨が降ったら — if it rains
• when for an expected event: 駅に着いたら — when you arrive at the station
• after/once when completion matters: 仕事が終わったら — after/once work is finished

English speakers sometimes hesitate because if and when signal different levels of certainty. With たら, context often carries that distinction. Add もし “if/by any chance” when you want to highlight a hypothetical condition: もし時間があったら、来てください。 The sentence remains grammatical without もし.

The result can express the speaker’s choice

One reason たら is so useful is that the result clause can contain an intention, invitation, command, request, or desire:

• 晴れたら、出かけよう。 — If it clears up, let’s go out.
• 分からなかったら、聞いてください。 — If you don’t understand, please ask.
• 日本に行ったら、温泉に入りたいです。 — When I go to Japan, I want to visit a hot spring.

This flexibility is important when you later compare たら with と, which normally describes automatic results and generally does not take a deliberate request or invitation as its result.

Plain and polite style can mix appropriately

The condition often uses a plain form even when the sentence is polite:

時間があったら、来てください。

This is not rude. Politeness is mainly carried by the sentence ending 来てください. ましたら and でしたら sound more formal and are common in announcements, customer service, and careful business speech: 駅に着きましたら、お電話ください。

よかったら as a social expression

Literally, よかったら is “if it is good,” but in offers and invitations it often means “if you like,” “if you’d like,” or “if that works for you.” It makes the offer less forceful:

よかったら、週末うちに来ませんか。 — If you’d like, would you like to come over this weekend?

Beyond the Basics / Advanced Use

You do not need to master every Japanese conditional at A2. For now, たら is a safe, versatile choice when one condition or event comes before a result. Later, however, you will meet several related patterns whose emphasis differs.

Form	Main emphasis	Example and meaning
たら	A specific condition or sequence; highly versatile	暇だったら、電話してください。 — If you’re free, please call.
ば	A logical or general condition	安ければ、買います。 — If it is cheap, I’ll buy it.
なら	“If that is the case”; often responds to known information	日本に行くなら、京都がおすすめです。 — If you’re going to Japan, I recommend Kyoto.
と	An automatic, habitual, or predictable result	春になると、桜が咲きます。 — When spring comes, cherry trees bloom.

The distinctions are tendencies rather than one-word translation rules. Both 安かったら買います and 安ければ買います can mean “I’ll buy it if it’s cheap.” The たら version readily presents a concrete situation; ば often sounds more like a condition logically sufficient for the result.

With なら, the condition does not have to happen before the result. If someone says they are going to Japan, you can reply 日本に行くなら、京都がおすすめです: the recommendation is useful before the trip. By contrast, 日本に行ったら、京都に行きたいです places going to Kyoto within or after the realized trip.

A past event followed by a discovery

In narratives, Vたら can mean “when I did V, I found…” The second event is often something the speaker did not control or expect:

窓を開けたら、雪が降っていました。 — When I opened the window, I saw that it was snowing.

Here, opening the window did not cause the snow. It created the point at which the speaker discovered it. This use helps explain why translating たら only as “if” is too narrow.

Counterfactual wishes and regrets

A condition can be presented as contrary to reality—a counterfactual, meaning an imagined situation that did not happen or is not true. Patterns with のに often express regret:

もっと早く出たら、間に合ったのに。 — If we had left earlier, we would have made it.

Context and the result clause show that the condition was not fulfilled. This is a later use; beginners only need to recognize that past time and unreal meaning come from the whole sentence, not from たら alone.

たら vs とき

とき means “time/when” and identifies the time surrounding an event; it does not inherently set an if-condition. Compare:

• 日本に行ったら、友達に会います。 — When/if I go to Japan, I’ll meet my friend. The trip is the condition for the next action.
• 日本に行ったとき、友達に会いました。 — When I went to Japan, I met my friend. This reports what happened on that occasion.

The form before とき also helps locate events relative to one another, so it deserves separate study rather than being treated as a direct replacement for たら.

Practice Tips

1. Build forms in two steps. Take five familiar words each day, make their plain past forms, and then add ら: 書く → 書いた → 書いたら; 忙しい → 忙しかった → 忙しかったら. Include a verb, an い-adjective, a な-adjective, and a noun.
2. Finish practical sentence starters. Complete prompts such as 雨が降ったら…, 仕事が終わったら…, and 時間がなかったら… with decisions, requests, or plans that are true for you. This trains meaning as well as form.
3. Classify what you hear. When you notice たら in conversation, ask whether English would naturally use if, when, or after. Then check whether the first event is a possibility, an expected event, or a completed step before the result.

Related Concepts

• Prerequisite: た-Form (Past Plain) — たら is built directly from this form.
• Next step: Ba Conditional — compare たら with the more logical or general ば condition.
• Next step: Nara Conditional — learn how なら responds to a situation or topic already under discussion.