The answer is actually quite simple -
6 days and 1 holiday!
Exodus 20:11
"For in six days the Lord made the heavens and the earth, the sea,
and all that is in them, and rested the seventh day..."
Some people say the days had to be very long because they want to believe in Evolution. But the Bible does not say this.
We need to trust God that He would not try to confuse us about something this important.
If the Bible does not mean what is says, then how can we ever understand it?