It is usual to say AからB without まで when you use a range in place of a number, and you repeat units. Therefore, “for two to four hours” is 2時間から4時間. 2時間[乃至]{ないし}4時間 is a very formal way to state the same thing, as ssb stated.
Your sentence has a few other incorrect or unnatural points.
- As oldergod stated, the usage of を is incorrect. The duration of an action does not take any case particle.
- It is awkward to mix kanji numerals and arabic numerals apparently without reason.
- This is subtle, but I feel that it is more natural to place 普段 at the beginning of the sentence, because 1日に2時間から4時間 is a single meaningful unit.
The resulting translation:
I usually study for two to four hours a day.
普段1日に2時間から4時間勉強する。
(It is strange to say 2時間から4時間まで here, but I am not sure why. I hope that someone can clarify the difference between AからB and AからBまで.)