Try your hand on the Stardate Calculator. Enter a stardate.
Using this calculator is simple. To find out what the current Stardate is, type in today's month and day, and the current room year for the roleplay (ie 2297), then the current time (as a rule, the room uses GMT time as the "standard") and hit Engage. Its that simple. The readout beside "Stardate" tells you the current Stardate!
Or an "Earth date"