Difference between Since and For
There are many pairs of words you might come across when you are learning English that seem to be used for the same purpose, but actually work differently. Since and for is one of those pairs. Both words also have other uses, so don’t worry if you’ve seen them in other contexts.
Since and for are two words that are used for similar, but not exactly the same, purposes. They work in a similar way to the Past Perfect Simple and Past Continuous tenses, and relate to when events happen.
Use since to indicate the beginning of a time period until the present. Since is used for the starting point of actions, events or states of being. Since can only be used with the perfect tenses.
> I have known her since June.
> Allison hasn’t been to that restaurant since her birthday.
> He’s wanted to learn about penguins since we went to the zoo.
Use for when you’re talking about an amount of time – how long something happens. Usually, you use it with a period of time. It can be specific or general. For can be used with all tenses.
> I have known her for 2 years.
> Allison hasn’t been to that restaurant for a few months.
> He talked about penguins for the entire trip to the zoo.
> Gennaro will live in London for 6 months.