The following are the three differences between concave and convex mirrors:

• A concave mirror is a spherical mirror with an inwardly curved reflection surface, whereas a convex mirror is a spherical mirror with an outwardly bulged reflecting surface.
• A concave mirror has a converging character and is so-referred to as a converging mirror, whereas a convex mirror has a diverging nature and is thus referred to as a diverging mirror.
• The focal length of the concave mirror is negative and the focal length of the convex mirror is positive.