As Foolstroupe says tunes with metronome markings will usually specify something like QuarterNote = 120 to indicate a tempo of 120 QuarterNotes per minute. But you might find that sometimes the unit may not be the beat. In 3/4 It might show Dotted-HalfNote = Number or in 3/8 Dotted-QuarterNote = Number, telling you how many bars per minute. Similarly in 6/8 or 9/8 you might get Dotted-QuarterNote = Value (with 2 or these or 3 of these respectively to the bar). In 2/2 or Cut 4/4 (C with a vertical line through) the tempo might be indicated with HalfNote = Value. You can always convert these to get beats on each note in the bar by multiplying the Value up eg if the tune is 6/8 and tempo is given as Dotted-QuarterNote = 60, then each Eighth note will be at tempo of 3*60 = 180. But usually the beat value is specified.

For tunes without metronome tempo markings you can use the following as a guide:

  Largo           40 -  60
  Larghetto       60 -  66
  Adagio          66 -  76
  Andante         76 - 108 
  Moderato
  Allegro
  Presto
  Prestissimo