Question: are all door hinges the same size?
Answer: The size and weight of the door will determine the size and number of hinges. Usually, you will replace the old ones with the same size and quantity. ... Most residential doors are between an 1 3/8" and 1 3/4" thick. So the normal size hinges for a residential door are 3" x 3" or 3 1/2" x 3 1/2".