- I am planning to do it in the next ten minutes.
- I am planning to do it for the next ten minutes.
Do the two sentences mean the same thing? I am sure using for is correct, but I want to know whether using in changes the meaning.
No, they don't necessarily mean the same thing.
Grammatically, both are correct. Semantically, however, they are different.
It's a question of duration in this case.
The first example means that you are going to start and possibly complete "it" sometime in the next ten minutes. You could start three minutes from now and finish seven minutes from now.
The second example means that you are going to do the action for the entire duration of the next ten minutes.