I think the Rambam says that each hour of sleep before chatzos halailah counts as double, so if you want to get the equivalent of 8 hours, you could go to sleep at 10:30 and wake up at 4:30. Not a great idea to go to sleep late and try to get up early. That’s often burning the candle at both ends.
If you feel rested and can function on less sleep then by all means sleep less, but if not, then you need to get the amount of sleep that your body needs. How old are you? Teenagers need more sleep usually than adults because they are growing.