How old would Moses be if he were still alive?
For this question it is best to look in the Hebrew Bible for any evidence of Moses' life. According to Genesis, Moses' grandfather, Kohath, was alive at the time of the migration of the Israelites to Egypt and lived 133 years, while Moses' father, Amran, lived 137 years. The Bible says that the Israelites spent 430 years in Egypt, and an analysis of the biblical genealogies suggests that Moses led the Israelites out of Egypt around 1440 BCE. That means that the journey to Egypt would have taken place about 1870 BCE. We do not know how old Kohath was when he went to Egypt, but if he and his son Amran were capable of fathering a child at any time between puberty and the year of their deaths, then Moses was born between about 1855-1600 BCE. Moses would therefore be about 3,600 to 3,855 years old if he were alive today.
Or, if we work backwards from Moses' reported death in about 1400 BCE, at 120 years old, then Moses would be about 3535 years old if he were alive today.
Another tradition supported by some Jews is that he lived even more recently and would be about 3400 years old if he were alive today.
You see, the problem is that we have no reliable information on Moses, and have to rely on guesswork and assumptions. For more information about Moses, please see: http://christianity.answers.com/theology/moses-in-history-and-tradition