Also called a vertical piano, an upright piano is more compact than a grand piano due to the vertical structure of the frame and strings. The mechanical action structure of the upright piano was invented in London in 1826 and upright models soon became the most popular type of piano as their compact size made them more suitable for use in private homes.

The hammers move horizontally and return to their resting position via springs, which are susceptible to degradation.

Upright pianos with unusually tall frames and long strings have sometimes been marketed as upright grand pianos, but that label is misleading. Some authors classify modern pianos according to their height and to modifications of the action that are necessary to accommodate the height. Upright pianos are generally less expensive than grand pianos. They are widely used in churches, community centres, schools, music conservatories and university music programmes as rehearsal and practice instruments, and they are popular models for home purchase.