In the book Frankenstein By Mary Shelley How long has Victor been away from home, studying at Ingolstadt?
In Frankenstein chapters 8-11, we can deduce that Victor Frankenstein studies chemistry and natural philosophy in Ingolstadt for four years with Clerval, from 1788 to 1792. Then, he creates his monster that same year, late November 1792.
After Victor creates the monster, he nearly goes mad from mental and physical exhaustion. He is nursed back to health for the Spring. In early April 1793, Victor resumes his studies at Ingolstadt with Clerval. They study foreign (Oriental) languages together. He only studies for a few months, until William is murdered, at which point he returns home.