The right hair cut for your face makes a huge difference. A study reveals the correct hair styles for different face shapes.

For those with a square face, the ideal hair length is below collar bone at minimum and also mentioned that chin length hair and box like fringes should be avoided by those with a square face or a round face.
Those with a long face and a good height should opt for a length between their collar bone and chin that has fullness at the sides and must avoid parting their hair at the centre.
Source-ANI