MIDIflex takes as input a MIDI file of a real-time recording, made without the aid of a metronome, and outputs a MIDI file with the downbeats aligned on measure bars. To make that happen, you the user must prepare the input MIDI file by inserting markers of the type ">n", where "n" is the bar number, at the locations of notes you want to occur on downbeats. MIDIflex inserts tempo changes to compensate for adjustments it makes to the timing of notes and events. The output MIDI file sounds the same as the input MIDI file, but the score is formatted with downbeats aligned on measure bars. Information about the MIDI file in process appears as text in the main window, which you can save to a text file. Mf Calculator is available for you to calculate time intervals or to determine the location of a marker preceding a pickup phrase. MIDIflex includes a complete Users Guide in html and rtf formats.