How to use “for” and “since” correctly in a sentence.

When you speak about the duration of events or actions, using “since” and “for” is essential.  However, when and how to use these two words can also be confusing.  In this blog post we will explore the proper way to use each word, and how to avoid mistakes.  It’s time to fix this grammar error for ever!

For: When to use it

In a sentence about time, “for” describes a period of time that an action or event took place.  Remember that: a period of time, or an amount of time.

For example, if you want to talk about studying and emphasize the amount two hours, you would say, “I studied for two hours.”  In this sentence we don’t know when the studying took place.  All we know is that it lasted two hours.

You can be more specific in your sentence.  You could say, “I studied for two hours yesterday.”  Now we know when the studying happened.

It’s important to note that native speakers generally use “for” sentences when they don’t care about the specific starting point of the action or event.  With a “for” sentence, you emphasize the duration or length of the action or event.

If the starting point is as important (or more important) than the length of the action or event, then you should consider “since.”

For: How to use it

A “for” sentence is always followed by a period or length of time.  For example:

  • for two hours
  • for 10 years
  • for one minute
  • for half a day
  • for my whole life
  • for as long as I can remember


You can use a “for” sentence to talk about the past or future.  This is a big difference between “for” and “since.”

  • I worked for 8 hours yesterday. (past)
  • I have worked at this company for five years. (past perfect)
  • I will work for two more weeks. (future)


Making questions with “for” sentences can be tricky.  Often it’s easier and more natural just to leave out “for” in questions.

  • Correct: How long have you lived here?
  • Correct: For how long have you lived here?
  • Incorrect: How long have you lived here for?

More Examples:

  • He has played football for 15 years.
  • I haven’t checked Facebook for a month!
  • My sister called me and talked for three hours.
  • This road has been under construction for ages. (“ages” = an amount of time the speaker thinks is excessive)
  • I’m going to visit Bali for two weeks in September.
  • How long did you live in California?


Since: When to use it

In a sentence about time, “since” describes the beginning point of an action or event that continues to the present.

With “since,” the length of the event or action is not as clear as when using “for.”  Instead, if the speaker feels the starting point of the event or action is more impressive than the duration, the speaker will use “since.”  It’s often left to the listener to calculate the length of the action or event.

For example, if you think it’s impressive that you started studying at 6 am this morning and continued studying to the moment of speaking, you could say, “I have been studying since 6 am.”  In this sentence the listener will assume the length of studying is from 6 am until that moment.  So if you say this sentence again two hours later, the listeners will assume the length of studying is two hours longer.

Since: How to use it

A “since” sentence is always followed by a specific point in time.  This point is when an action or event began.  For example:

  • since 2001
  • since I was 10 years old
  • since Monday
  • since the beginning of time
  • since this morning
  • since 2 pm


You should only use “since” to talk about the past.  Specifically, a past event that continues to the present moment.  “Since” is generally only used with perfect tenses.  Avoid using “since” with the simple past.

  • He has lived here since 2001.
  • I have studied English since I was 10 years old.
  • It has been raining since yesterday evening.


“Since” questions can be formed just like “for” questions.  In other words, avoid including “since” in the question.

  • How long have you known Karen?
  • How long have you been reading that book?

More Examples

  • He has played football since he was in first grade.
  • I haven’t checked Facebook since last month!
  • She and I have been friends since we were kids.
  • The weather has been cold since October.
  • I have lived in this town since I was born.
  • Sam has loved to tell stories ever since he learned to talk.

Note: Add “ever” before “since” emphasizes that the speaker feels the duration of the action or event is unusually long or impressive.