PHP round time() up (future) to next multiple of 5 minutes

Question

How do I round the result of time() up (towards the future) to the next multiple of 5 minutes?

Answer 1

 $now = time();     
 $next_five = ceil($now/300)*300;

This will give you the next round five minutes (always greater or equal the current time).

I think that this is what you need, based on your description.