So how do you figure out if you are creating a good calorie deficit to lose weight? Do you take your subtract your total calories consumed and total calories burned then take that number and subtract it from your BMR/RMR? And if that is the case, do you use the BMR/RMR that takes into account activity level or do you use the number that would assume you are only at rest? I really don't want to eat below 1400 calories because that is hard to sustain and very unhealthy. I just wanna see how much working out and to what extent do I need to lower my calories from food but to do that I need to know what the basic formula is. I'd rather exercise more and slightly lower my daily calories because I tend to have a problem with eating below 1400 calories a day.

I did it by tracking long-term trend in weight. But that requires an extended period of time.

Total calories burned (regardless of whether you really mean "total," or really mean "from unusual physical activity") is hard to calculate accurately, IMHO.

Assuming you can get reasonable estimates to work with, the calculation is calories eaten minus calories burned, where the calories burned number includes both your basal requirements and your activity calories. (There are also some other numbers you could toss in there if you were so inclined, but measurement slop is going to make them pointless anyhow.)

BMR = basal metabolic rate. RMR = resting metabolic rate. Neither of those contain an activity-level modifier. That modified number could be considered "maintenance calories" or something like that, but it's neither BMR nor RMR.

What worked for me was to set my Fitday settings at "seated work," and record any unusual activity using its numbers for calories burned. So if I walked for 30 minutes at 3.5mph, I got credit for 65 net calories. That worked reasonably well for me, but I have no reason to believe it would work reasonably well for everyone.

I agree with this method.

To get how many calories I need per day without any exercise I multply my BMR by 1.2 (basically sedentary). Which gives me 1700 calories as my daily maintenance calories.

To get my daily defecit I subtract my daily calories from my maintenance and then add in my exercise calories.