Many people use “further” and “farther” interchangeable, but, in fact, they mean slightly different things. “Farther” refers to a physical distance, while “further” refers to a figurative distance. In most cases you will use 'further', but for the MOST part 'further' is more figurative, and 'farther' is more literal. Example: I was further along in my education, then I would have imagined. The nearest house was much farther than she thought.

If you are concerned about which word to use, the answer to this question is very simple - you never actually need to use the words 'farther' or 'farthest'. 'Further' can be used for both physical distances, as in "Drive further down the road", and figurative distances, as in "There were no further questions". . "Farther" can only be used for physical distances. So, if you want to avoid making mistakes, just use 'further' in all cases.

Farther is used in referring to literal physical distance: - Once you pass the big oak tree, the crossroads is two miles farther. - The sofa need to be a foot farther to the right. Further used to be used only in figurative or abstract senses: - I need to think about this decision further. - He was bitterly disappointed that he could not continue his education further. But further is now also acceptable for physical distances: - This is her office, and my office is three doors further down the hall.