Understanding “Since”

“Since” is an incredibly versatile and useful word. Depending on the sentence, “since” might be used as an adverb, a preposition, or a conjunction!

Unfortunately, because “since” is used in so many ways, it can also be very easy for both native and non-native speakers to use it incorrectly. Misuse of the word “since” is one of the most common errors that our TextRanch editors see every day.

One reason why so many people get mixed up about “since” is because it has different meanings, depending on the context. The first meaning of “since” is related to time, while the other one is related to cause/reason.

Let’s break these down and take a closer look at them.

A period of time

When you see “since” in a time context, it usually refers to the start of a period of time that runs until the present.

Note that the sentences below all include a form of the verb “to have” next to another verb. This signifies that events or actions continued (or are continuing) over a period of time.

Jon and Caroline have been married since 1998.

Since he graduated from college, Christopher has worked at many different jobs.

Since the terrorist attack, tensions between the two factions have been escalating.

Roberto hasn’t seen any of his cousins since their grandfather’s funeral.

Hamid came down with Covid last winter, and he hasn’t felt well since then.

A reason why

“Since” is also used in sentences that give a reason for something. In these contexts, “since” serves as a preposition, similar to “because”. Sometimes “since” and “because” are used interchangeably, but “since” has a more formal tone.

Since it’s raining, we cannot take the dog out for a walk.

Pavel needs to buy a car since he lives so far from his job.

Since some of the children have allergies, the school does not allow anyone to bring foods that contain peanuts.

Incomplete sentences with “since”

One of the biggest problems with “since” is that it often serves as the beginning of an incomplete sentence. The following are some pretty typical examples:

Since Pedro moved away.

Since we cannot complete the foundation work without the proper permits.

Since Li went on extended leave.

Since the last time Kaori traveled to Tokyo.

Although each one of these has a subject and a verb, they are not full, complete sentences. They do not form a complete thought; we are left wondering what happened to the rest of the sentence. We covered this in a previous article, but it happens so often with “since” that it warrants special attention.

Therefore, when you are starting a sentence with “since”, be sure that the sentence is complete. If it isn’t, look for ways to connect it to either the sentence that comes before it, or the sentence that comes after it.

Since Pedro moved away, the house next door has really deteriorated.

Since we cannot complete the foundation work without the proper permits, nothing is getting done at this site.

Everyone has been working extra hours since Li went on extended leave.

Hotel rates have increased substantially since the last time Kaori traveled to Tokyo.

“Since” or “for”?

Another common writing problem is confusion over when to use “since” and when to use “for”. One major difference is that “for” can be used to describe a period of time in the past, present, or future. Meanwhile “since” has to start at a point in time in the past, even when that time period continues into the present. “Since” cannot refer to a period of time in the future.

The key to knowing the difference between “for” and “since” is to look for a starting point. If you see a starting point that indicates a particular period of time, use “since”. Otherwise, use “for”.

Below are some similar sentences, some of which use “since” and some of which use “for”. The ones that use “since” have the starting point highlighted in boldface. The ones that use “for” do not have a starting point.

I have lived in New York since 2008.

I have lived in New York for a long time.

I have lived in New York since I started working on Broadway.

I have lived in New York for a few months.

I have lived in New York since Ed Koch was the mayor.

I have lived in New York for fifteen years.

“Wait!” you might be saying. “Isn’t fifteen years a starting point? Wouldn’t since be correct in that sentence instead of for?”

No, “fifteen years” is not a starting point. Sure, you can count back the number of years and figure out the starting point. However, think about what would happen if you were reading that sentence in 2024 or 2025 and subtracted fifteen years. You would have a different starting point than someone reading that sentence in 2023. Therefore, “for” is correct and “since” is incorrect.

Understanding all the different meanings of “since” and knowing how to identify incomplete sentences should help you avoid mistakes. However, if you still have questions about when or how to use “since”, click the blue box below. One of our TextRanch editors will look at your writing and let you know if you are on the right track.