Is there a mission timer in StarCraft II?
There's a built in timer since patch 1.1.
It's in the options gameplay -> display in game timer.
You can save your mission and then view the elapsed time on the load saved mission screen, but that is the only way to view it in-game as far as I know. As for keeping track of your time on your own, keep in mind that game time and real time are different things, and the achievements are for game time.
- Normal speed is equal to real time.
- 1 real minute playing on fast is about 1.2 minutes of game time
- 1 real minute playing on faster is about 1.38 minutes of game time