Since vs. For: What’s The Difference?

Since and for are often confused in English because they are both prepositions of time. Read on to learn about since vs. for and their key differences.

Some words are misused when working with English grammar because they have similar meanings. The words “since” and “for” are some of these words.

These two prepositions have different uses depending on the verb tense used in the sentence. Therefore, understanding how to use them correctly will make your writing more precise. This guide will show you how to use them correctly in your writing. You might also be interested in our objective vs. subjective explainer.

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Since vs. For: What’s The Difference?

The words “since” and “for” are prepositions that deal with time. Because they are similar, they are sometimes misused, especially by unfamiliar learners with English grammar. However, they both have specific uses that can help you keep them straight. You can also check out our loath vs. loathe explainer.

Meaning of and Uses of “For”

According to the dictionary, “for” has several meanings when used as a preposition. These include:

  • A function word that indicates a purpose
  • A function word to indicate a goal
  • Function word to indicate the recipient of something
  • Meaning “because of”
  • Meaning “in place of”
  • Meaning “in spite of”
  • Meaning “in honor of”
  • A function word to indicate a period of time

This final definition most frequently gets confused with “since.”

The word “for” is most commonly a preposition in a sentence, but it can also be used as a conjunction. In this case, it means something similar to “because.”

“For” as a Preposition Referring to Periods of Time

For as a preposition referring to periods of time
If you are following the preposition of time with a specific period of time, you will usually use “for”

The definition of “for” that refers to periods of time is the one most commonly confused with “since.” The pattern of these sentences typically follows this:

  • for + period of time

The time period may be specific, like “three weeks,” or vague, like “years” or “days.” Regardless, if it is not a particular point in time, you will use the preposition “for.”

Verb tense has less of an impact on the use of this preposition. Depending on the context of the sentence, you can use it with past, present continuous, past continuous, and even future tense. If you are following the preposition of time with a specific period of time, you will usually use “for.”

Here are some example sentences:

  • Last week, we were at the DMV for three hours. (simple past tense)
  • Tomorrow, we will plan to be gone for two hours. (simple future tense)
  • I am traveling for four days. (Present continuous tense)

Other Uses of “For”

“For” has other uses that are not related to time. Here are some example sentences using “for” in other ways:

  • The gift was for my mother.
  • She gave him a coupon for his trouble.
  • The quarterback ran hard for the endzone.

Meaning of and Uses for “Since”

“Since” is another of the prepositions of time and one that can easily be mixed up with “for.”

According to the dictionary, the definition of “since” when used as a preposition is “in the period after a specified time in the past.”

“Since” can also be an adverb and a conjunction. When used as an adverb, it means “from a definite past time until now” or “after a time in the past.” As a conjunction, it means “at a time in the past after or later than.” It can also be a synonym for “because.”

“Since” as a Preposition of Time

The use of since as a preposition of time always refers to a set or specific time in the past. So, for instance, you could say:

  • George has been sick since last Tuesday.

Last Tuesday is a specific time in this sentence, but the sentence does not specify a particular time, like a certain number of days.

When used as a preposition of time, “Since” is always paired with a perfect tense verb. However, it is not used with the perfect future tense because “since” always refers to a specific point in the past. Therefore, it can show up with present perfect tense and past perfect tense verbs.

Here are some example sentences:

  • The baby has been awake since 5 a.m. (past perfect tense)
  • Samual has driven a Volvo since his 16th birthday. (present perfect tense)

In both of these sentences, the use of the perfect tense verb and the fact that the sentence refers to a specific moment in time dictate the use of the word “since,” so they are grammatically correct. 

“For” vs. “Since” – Getting It Right

If you can remember the following clause, you will be able to get “for” and “since” right:

  • Use “for” when talking about a period of time.
  • Use “since” when talking to a specific point in time.

Sometimes, the verb tense is not a clear indicator of which word to use because “for” can work with almost any verb tense. For example:

  • They have been our neighbors for ten years.
  • They have been our neighbors since 2010.

Because ten years is a period of time and 2010 is a specific point in time, these two sentences use the prepositions correctly. You may also find our into vs. in to explainer helpful.

“Since” and “For” as Conjunctions

Both “since” and “for” can be conjunctions, and they have a very similar meaning in this use. Both mean something similar to “because.” When used as a conjunction, the words are interchangeable.

Here are some example sentences:

  • He did not go to the meeting, for he was struggling with illness.
  • The dog barked loudly since it could not see who was outside.

You could substitute the word “because” for the conjunction in both of these sentences. The use of “for” as a conjunction is less common than “because” or “since,” but still grammatically correct.

A Final Word on Since Vs. For

Both “since” and “for” are seemingly simple words in the English language, but because they both work as prepositions of time or conjunctions, some writers will confuse them. But, like many confusing words, they have specific meanings that, once you learn, you can keep straight more easily.

If you are talking about a period of time, you will use “for.” If you talk about a set date or specific time in the past, you will use “since.”

After you get the hang of these two rules, you will find that using the correct word comes more naturally. Take your time and learn the difference, and soon you will write English with confidence using prepositions correctly.

You might also be interested in our was vs. were explainer.

FAQs About Since Vs. For

What part of speech is “since?”

The word “since” has several parts of speech. It can function as in the English language. If a noun phrase follows it, it is a preposition. If it is part of a verb phrase, it may be an adverb describing the verb. It can also be in conjunction with a similar meaning to “because.”

What part of speech is “for?”

For is usually used as a preposition. It has several meanings as a preposition, but this is the most common part of speech for this little word. However, it can also be a conjunction that has a similar meaning to “because.”

To learn more, check out our guide on English grammar clauses!

  • Nicole Harms has been writing professionally since 2006. She specializes in education content and real estate writing but enjoys a wide gamut of topics. Her goal is to connect with the reader in an engaging, but informative way. Her work has been featured on USA Today, and she ghostwrites for many high-profile companies. As a former teacher, she is passionate about both research and grammar, giving her clients the quality they demand in today's online marketing world.