The world's premier FREE website for learners and teachers of English. Est'd 1997

for and since for Time

We lived there for five years.
He has been away since Tuesday.

We often use for and since when talking about time.

for + period: a "period" is a duration of time - five minutes, two weeks, six years. For means "from the beginning of the period to the end of the period".

since + point: a "point" is a precise moment in time - 9 o'clock, 1st January, Monday. Since means "from a point in the past until now".

Look at these examples:

a period
from start to end
a point
from then to now
>===< x===>|
for 20 minutes
for three days
for 6 months
for 4 years
for 2 centuries
for a long time
for ever
since 9am
since Monday
since January
since 1997
since 1500
since I left school
since the beginning of time
all tenses perfect tenses


For can be used with all tenses. Here are a few examples:

We do not use for with "all day", "all the time":


Since is normally used with perfect tenses:

We also use since in the structure "It is [period] since":

Both for and since also have other meanings, with no reference to time. Here are some examples:
  • This is for you.
  • Is this the train for London?
  • Since you ask, I'll say yes.
  • Since he didn't study, he didn't pass the exam.