How many calories burned in a 30 minute jog?

The answer depends on several variables. How much do you weigh? how fast are you moving? Uphill or flat surface the entire jog? Generally, jogging or running should burn 300-400 calories per hour, but again, it does depend. You can go to the gym and use a treadmill or other cardio machine to see exactly how long you've exercised, and how many calories it's burned, or you can buy a pedometer from nearly any store that sells fitness equipment which will also tell you.