Translation guide
The act of sleeping longer than intended, often resulting in being late or missing something.
I overslept. (casual)
To sleep past the intended time, usually by accident.
The most common and neutral way to say 'oversleep'. It implies accidentally sleeping past the intended time.
I overslept this morning and was late.
A very common, slightly more casual way to say 'oversleep'. Often used as a noun (寝坊).
Literally 'sleep too much'. Can be used for oversleeping, but also for sleeping excessively long without necessarily being late.
To oversleep specifically because the alarm didn't go off or was turned off.
A natural way to explain that the alarm didn't ring and you overslept.
My alarm didn't go off and I overslept.
Describes the common scenario of turning off the alarm and going back to sleep, leading to oversleeping.
To describe someone who frequently oversleeps.
Both mean 'oversleep', but 寝坊する is slightly more casual and often used in spoken Japanese. 寝過ごす is neutral and can be used in both spoken and written contexts. 寝坊 can also be used as a noun (e.g., 寝坊した).
In English, 'sleep in' can mean intentionally sleeping later than usual. In Japanese, 寝過ごす and 寝坊する usually imply an accident. For intentional sleeping in, use ゆっくり寝る or 朝寝坊する (which can be intentional or accidental depending on context).
I overslept and missed the train.
休みの日はいつも寝過ぎてしまう。
On my days off, I always end up sleeping too much.
I turned off my alarm and went back to sleep, then I overslept.
I often oversleep, so I set three alarms.