When can we omit 'for' before time noun ?

In below examples, the preposition 'for' is omitted before a time frame is specified.

In the afternoon we drive 20 minutes to the Eden Project.

We work 5 hours a day.

Walk 30 minutes every day.

We are going to the town two hours from now.

But in case of a similar verb 'run', I've never seen such omission of 'for'.

  • 1
    "I run 20 minutes a day." can easily and correctly be said.
    – Peter
    Commented Jun 15, 2016 at 3:53
  • 1
    You can omit 'for' in most conversations and informal writings. In fact, even in formal writings: as inclusion of a 'for' makes a sentence heavy and clumsy.
    – tom
    Commented Jun 15, 2016 at 4:45
  • A complicated subject and possibly a duplicate of this question here and this one on ELU, both of which have good answers.
    – PerryW
    Commented Jun 15, 2016 at 5:21

1 Answer 1


With longer periods of time you should probably use "for." If the period of time is unspecified, "for is definitely required. For example, "I searched for hours!" "For" always specifies duration, so you could never say "we are going to the town for two hours from now." Idiomatically, you can use "for" to express a specific time, like "we're going to the town for 2:30." That usage of "for" means "we expect to arrive at such a time." In general, "if you can append "a day," "a week," "a month," or "a year," to the end of a sentence, you can omit the "for." "I fly six hours a week between Vancouver and LA." "They're open six hours a day." While you can use "for" in those circumstances, it usually doesn't carry any specific meaning.

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