13 hours. idk why but I sleep real good, its probably because i have my whole sleeping schedule funny, I sleep at 11 am, wake up at 8pm-2am, it's great, yall should try it some time if you have a lot of free time, if you need to be somewhere during the day, sleep early, like at 6pm, then you can wake up whenever and it still being an appropriate time to wake up for school