Since vs for
Use since with a starting point in the past, like since 2010 or since Monday. Use for with a length of time, like for three years or for a week.
Since answers the question since when, and for answers the question for how long.
since preposition, conjunction
From a point in the past up to now. After it comes a starting time, like 2010, or an event, like we moved here.
- I have been awake since six o'clock.
- We have not spoken since we argued last summer.
for preposition
Used to say how long something lasts. It comes before a length of time, such as ten minutes, three years, or the whole summer.
- They have been married for twenty years.
- I lived in Spain for two years before I moved home.
Watch out
- Since can also mean because, when the reason is already known or obvious. This use is about a reason, not about time.Since the store was closed, we went home.
- Since can come at the end of a sentence with no time after it, often as ever since. It means from that time until now.He fell off his bike and has been careful ever since.
- For does not have to reach up to now. It can describe a length of time that is already over.The store was closed for all of August.
Test yourself
I have lived in this city blank 2015.
Show answer
since. 2015 is the starting point, so use since.
We waited at the station blank two hours.
Show answer
for. Two hours is a length of time, so use for.
She has been much happier blank she moved to the coast.
Show answer
since. Moving to the coast is the event when her happiness began, so use since.
My parents have been married blank thirty years.
Show answer
for. Thirty years tells how long, not when it started.