An MP13 file is a project created by version 13 of Multisim, a program used to analyze, design, and simulate printed circuit board (PCB). It contains references to one or more circuit designs stored in .MS13 files. MP13 files also store simulation results, reports, and documents.

MP13 files are used to organize and manage multiple designs in a project. The MP13 file is one of the main file types associated with Multisim, along with the MS13 file. You can simply double-click the MP13 file to open it in Multisim. Multisim appends a number to project file extensions, which indicates the Multisim version that created the project. For example, Multisim 11 creates the .MP11 file extension and Multisim 12 creates the .MP12 file extension. Also, Multisim supports older project formats, which means that version 14 of Multisim can still open an .MP8 project created by version 8 of Multisim.