Zorg SpaceWhat is the difference between “for” and “since”?
Short answer
Use for with a length of time — how long: for three years, for two hours, for a long time. Use since with a starting point — from when: since 2019, since Monday, since I was a child.
Both are very common with the present perfect when a situation started in the past and continues now: I’ve lived here for six years = I’ve lived here since 2019.
The rule in one table
| for + a period | since + a point in time |
|---|---|
| for ten minutes | since ten o’clock |
| for three days | since Tuesday |
| for two weeks | since the 1st of May |
| for six months | since March |
| for years | since 2015 |
| for ages | since I moved here |
A quick test: if you can put “how long?” in front of it, use for. If you can put “from when?” in front of it, use since.
With the present perfect
When the situation is still true now, English uses the present perfect (or the present perfect continuous for ongoing activities):
-
I’ve known her for ten years.
we met ten years ago and still know each other
-
She’s worked here since 2021.
she started in 2021 and still works here
-
We’ve been waiting for twenty minutes.
the waiting continues now
-
It’s been raining since this morning.
it started this morning and hasn’t stopped
“For” works with other tenses too
For is not limited to the present perfect. It works with any tense when you talk about a duration:
-
I lived in Spain for two years.
finished — I don’t live there now
-
We’ll stay for a week.
future
-
She’s going to study for an hour.
future plan
Since, as a time word, almost always goes with perfect tenses, because it describes a period that runs from a point up to another point.
A common structure with since is: It’s been + time + since + past simple: It’s been five years since we met.
“Since” can also mean “because”
In more formal English, since can introduce a reason: Since you’re here, could you help me? Context makes it clear which meaning is intended.
“For” or “ago”?
- ago counts back from now to a point in the past and goes with the past simple: I moved here six years ago.
- for measures the length of a period: I’ve lived here for six years.
Both sentences can describe the same facts.
Common mistakes
-
Not: I live here since 2020.
Better: I have lived here since 2020.
-
Not: I’ve worked here since three years.
Better: I’ve worked here for three years.
-
Not: I am waiting for twenty minutes.
Better: I have been waiting for twenty minutes.
-
Not: I know him since we were children.
Better: I have known him since we were children.
-
Not: I’ve lived here for 2019.
Better: I’ve lived here since 2019.
The tense mistakes come from languages that use the present tense for these situations: German Ich wohne seit 2020 hier, Dutch Ik woon hier sinds 2020, Spanish Vivo aquí desde 2020, French J’habite ici depuis 2020. In English, a situation that started in the past and continues needs the present perfect.
Practise
Answer these about yourself, with both for and since:
- How long have you studied English?
- How long have you lived in your current home?
- How long have you had your phone?
-
I’ve studied English for four years.
I’ve studied English since 2022.
In short
- for + length of time; since + starting point.
- For situations continuing to now, use the present perfect with both.
- For works with all tenses; since (time) goes with perfect tenses.
- Ago + past simple counts back from now.
Lessons on this in the library
Practise it in Zorg Space
Reading an answer is the first step. In the app, the same grammar becomes exercises with instant correction, new words come back for review just before you would forget them, and you listen and speak as well.
Practise in Zorg Space