Because vs Since: Which One Do You Need?
Because always gives a reason. Since gives either a reason or a point in time — which is why it can be misread.
We left because it was late. I have not seen him since Tuesday.
The test that settles it
Try replacing the word with from the time that. If that reading is possible, the sentence is ambiguous, and because is the safer word.
“___ he moved to London, he has been happier” → could mean either, so rewrite.
“We stopped ___ the road was closed” → only a reason, so either works — but because is clearer.
Because: reason only
It has one job, which is why it never misleads. It answers the question why.
The match was cancelled because of the rain.
She left early because she felt unwell.
Because the file was corrupted, we lost the data.
Does it answer why? Then because fits.
Since: time, or a softer reason
Its original sense is temporal — from a point in the past until now. It also introduces a reason, usually one the reader already accepts.
I have worked here since 2019.
Since you are already here, you may as well stay.
Much has changed since then.
Could you say from the time that? Then it is the time sense.
Side by side
| Because | Since |
|---|---|
| Reason | Time, or a given reason |
| Never ambiguous | Can be read two ways |
| Answers why | Answers why or when |
| Because it broke | Since Monday |
The exceptions
Since works well when the reason is already known to the reader and you are just acknowledging it: Since we all agree, let us move on.
Because in that position sounds heavier, as though the reason were news.
Since I left the company, I have been much happier. Does that mean happier ever since, or happier as a result? Only because or a rewrite settles it.
Where people get it wrong
| Incorrect | Correct | Why |
|---|---|---|
| Since it rained, the pitch was unplayable. | Because it rained, the pitch was unplayable. | A cause, so the unambiguous word. |
| I have been here because Monday. | I have been here since Monday. | A point in time. |
| due to the fact that it was late | because it was late | Four words doing one word’s job. |
| Since he retired, the department has struggled. | Because he retired, the department has struggled. | Only if you mean cause — otherwise leave since. |
Practice — choose the right word, then check yourself.
- We cancelled ___ nobody signed up.
- She has lived here ___ 2015.
- ___ you asked, I will explain.
- The road flooded ___ the drain was blocked.
- Nothing has changed ___ the meeting.
Show the answers
1. because 2. since 3. Since 4. because 5. since
Frequently asked
Can I start a sentence with because?
Yes. The old rule against it exists only because a fragment such as Because it rained. is incomplete. A full sentence is fine.
What about as?
As also does both jobs and is even more ambiguous than since. In writing that has to be precise, prefer because.
More words people confuse
