"For" and "since" are common English words that are used to talk about time and duration. It might not be obvious at first, but there is a clear difference in how they are used.
In addition, both also work as conjunctions to explain why something is the way it is. While "because" is usually used for giving reasons, "for" and "since" have differences in nuance that can affect how your statement sounds. We'll take a look at all of these uses and their details in this article.
Expressing periods of time
The prepositions "since" and "for" are used to express periods of time. Advertisements for brands with a long history often have "since" written together with the year the business started, as in "Since 1930." Here are some other common examples:
- since Monday
- since last year
- since then
- since it began
- since childhood
- since we last met
As you can see, "since" is combined with a specific point in the past to express the start of a period of time.
On the other hand, "for" is used in combination with a length of time to express duration, or how long something has existed or has been happening.
- for 20 years
- for a while
- for a long time
- for one hour
- for decades
- for a few months
So "since" focuses on when a period started, while "for" focuses on the period in total. To get a better understanding of the difference, look at the two ways to answer this "how long" question.
The first response refers to the starting point only, but the second response expresses the duration of time, from the start until the present.
Because it refers to a starting point, "since" is used in the perfect tense.
"For," however, can be used to talk about the past, present or future.
Explaining a reason or cause
We usually use "because" when giving a reason, and it can be used at the beginning or in the middle of a sentence. "For" and "since" can be used in the same way.
When using any of these words at the beginning of a sentence, separate the reason from the result with a comma.
Explaining reasons using “since”
Although it can go at the beginning or in the middle of a sentence, "because" is often used in the middle in daily conversations. "Since," however, is common in both positions. It also sounds a little more casual than "because."
Explaining reasons using “for”
"For" can be used just like the other two, but it is much more formal.
This usage is very old-fashioned. You may read it in a classic novel or hear it in a theater play, but you will probably never hear it used this way in a normal conversation. However, even if you don't have an opportunity to use it, it can be useful to know!
Practice makes perfect
Both "for" and "since" are common English words that are often used in similar situations, so it can be easy to confuse them. But if you look carefully, their differences will become clearer to you.
You'll need to actually use them often to strongly establish their usages in your mind. Luckily, it's not difficult to find examples of these words in real-life situations, so be sure to look and listen carefully for them.