What's the context? 

"I'm going to go work out" = I'm going to exercise. 

"I bet he works out" = I bet he does a lot of exercise.

"I hope it all works out" = I hope the outcome will be positive. 

"Don't worry, everything will work out" = Don't worry, the outcome will be positive. 

Thanks janos.

Correct, people generally say " I am going to workout " meaning they are going to the gym to take part in physical exercise.

Or workout, as in "everything will workout or worked out well"

thanks cathy