Crimping devices and methods

Devices and methods for crimping a prosthetic heart valve onto a delivery device are described. In some embodiments, valves are crimped over an inflatable balloon and between proximal and distal shoulders mounted on a shaft inside the balloon. Crimping methods can include multiple compression steps with the valve located in different axial positions relative to the crimping jaws at each different step. In some methods, the valve may extend partially outside of the crimping jaws during certain crimping steps, such that the crimping force is only applied to the part of the valve that is inside the jaws. Exemplary crimping devices can include two or more adjacent sets of jaws that close down to different inner diameters, such that different parts of a valve get compressed to different outer diameters at the same time during a single crimping step.