Exercise calories not syncing

rpapesr

I am having a hard time matching up my workout calories with the calories on MFP. I currently use the treadmill for running and walking but when I put these times/speed in the program the calories on here come up short of what the gym equipment says. Wondering which one to use or if anyone else is having the same problem. I hate to short myself by as much as 100 calories on a 800 caloried workout.