How long is a day in GTA V in real time?
A full day in GTA 5 takes 48 minutes real time.
One hour takes 2 minutes.
Game time stops when pausing, will automatically advance when starting some missions and using a bed to save will advance game time by 6 hours (Michael), 8 hours (Franklin) or 12 hours (Trevor).
Note: Game time does not stop when pausing in GTA Online.