I would like to add 24 hours to the timestamp for now. How do I find the unix timestamp number for 24 hours so I can add it to the timestamp for right now?
I also would like to know how to add 48 hours or multiple days to the current timestamp.
How can I go best about doing this?
You probably want to add one day rather than 24 hours. Not all days have 24 hours due to (among other circumstances) daylight saving time:
strtotime('+1 day', $timestamp);
A Unix timestamp is simply the number of seconds since January the first 1970, so to add 24 hours to a Unix timestamp we just add the number of seconds in 24 hours. (24 * 60 *60)
time() + 24*60*60;