Translation guide
How to express that something happened unintentionally, without planning, or by chance in Japanese.
The action was not intended; it happened by mistake or carelessness.
Adverb meaning 'carelessly', 'absentmindedly', or 'without thinking'. Used when you do something by accident because you weren't paying attention.
I accidentally told the secret.
I accidentally missed my stop.
Adverb meaning 'unintentionally' or 'against one's better judgment'. Often used for habitual or impulsive actions.
I accidentally ate too much.
I accidentally told a lie.
Adverb meaning 'involuntarily', 'without thinking'. Used when a reaction happens before you can stop it.
I laughed by accident.
I screamed by accident.
Te-form of 間違う (to make a mistake). Means 'by mistake' or 'erroneously'.
I accidentally deleted the email.
I accidentally pressed the wrong button.
Te-form of うっかりする, meaning 'to be careless'. Used to explain the reason for an accident.
I accidentally forgot my wallet.
Something happened without planning, as a result of luck or coincidence.
Noun/adverb meaning 'by chance', 'coincidentally'. Neutral and widely used.
I met him by accident.
Adverb meaning 'by chance', 'happened to'. Casual and very common in speech.
More emphatic form of 偶然, often used in writing or formal speech.
By accident, we were born on the same day.
Something happened without being planned or scheduled.
Adverb meaning 'suddenly', 'without thinking', 'on a whim'. Used for spontaneous thoughts or actions.
I remembered the past by accident.
I looked up at the sky by accident.
Adverb meaning 'casually', 'without much thought'. Implies doing something without a clear intention.
うっかり is for careless mistakes (forgetting, overlooking). つい is for giving in to temptation or habit (eating too much, lying). 思わず is for involuntary physical/emotional reactions (laughing, screaming).
I carelessly forgot the appointment.
I ended up buying sweets (even though I shouldn't have).
Tears came out involuntarily.
偶然 is slightly more formal and can be used as a noun (偶然の出来事 - a chance event). たまたま is more colloquial and often implies a one-time coincidence.
That's a coincidence.
I met her by accident at the station.
I accidentally broke the vase.
We met by accident.
I found that shop by accident.
たまたま通りかかった。
I happened to pass by.
We happened to be on the same train.
The words I said by accident hurt him.
I just happened to be there.