Usage of Ago vs Before - Difference between Ago and Before

Ago vs Before

 Ago and Before are almost same in meaning but differ in usage.

Usage of Ago :

Ago is used after an expression of time counted from present. The sentences with Ago are usually in simple past tense.

Example sentences for the usage of Ago:

I toured France 6 years ago ( "6 years" - expression of time  )

I saw the Taj Mahal 3 months ago ( "I have seen Taj Mahal 3 months ago" is wrong because it is not in simple past tense )

Usage of Before :

Before has two places of usage

1. It is used after an expression of time that counts back from a past moment. Such sentences are in past perfect tense.
2. It can also be used without an expression of time to mean 'any time before the point of time that is being pointed to'. Such sentences are in perfect tense.

TIP: Sometimes, Before is also used to mean 'already'. Such sentences may be used in simple past tense.

Example sentences for the usage of Ago:

I had toured France 6 years before I was married ( Type 1: "6 years" - expression of time from Marriage- past moment  )

I had seen the Taj Mahal before I toured France ( Type 2: There is no expression of time here and event could be any time, be it 1 year or 10 years, before touring France)

I have gone there before (Type 2: No expression of time and hence the event could be any time before 'now' )

I saw the movie before (Not wrong usage though the tense is simple past. Here 'before' means 'already')

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