for, since

For and since answer the question How long? With the present perfect, they say how long something has been true, up to now.

For

For + a length of time: for ten minutes, for three days, for a long time, for ages.

For also works with other tenses: I lived in Tokyo for a year. (and now I don't).

Since

Since + the point in time when it started: since Monday, since 9 o'clock, since 2019, since last summer, since I was a child.

How long

Ask with How long have you…? The question is in the present perfect too.

Common mistakes

The most common mistake is to use the present simple with for or since.

• × I live here since 2020. → I've lived here since 2020.
• × I am here for two hours. → I've been here for two hours.
• × I've lived here since five years. → I've lived here for five years.
• × How long are you married? → How long have you been married?
• × I've lived here for 2020. → I've lived here since 2020.