BMR ans weightloss confusion

Ok, last example; if I ate 2303 and burnt off 1131.9 in exercise, would I deduct my BMR from that to make a deficit of -548.1? (That was my day yesterday.)
I know I'm being frustrating, I'm just worried about doing the wrong thing

Eat 2300 daily.

Exercise the number of hours you put in to the calculator to estimate the TDEE level.

You will lose weight.

If you miss 1 hr of workout that you had planned - skip 100 calories that day. If you happen to make it up - eat an extra 100 calories that day.

Yes - you are very much confusing yourself. I'd suggest rereading most of the response again all at once, will likely sink in better now.

Just so you know too, all stresses can fight against fat and weight loss.
Diet is a stress, frequent intense exercise is a stress, food allergies are a stress if you have any, life can be a stress.

While it may seem more exercise will increase the daily burn, and therefore the amount of deficit you could take, and the amount of weight you could lose - as an additional stress you could very well find that your body adapts and you don't lose that much extra anyway.
In which case it would have been wiser to exercise less but smarter, and accept slower weight loss that will likely happen anyway.

Also confirm the food side of the equation - weigh everything, not measure unless liquids, weigh.

Thanks. After looking into it more, I was right. I was just doing the sum the other way round. I was taking the food I consume, minus my BMR and exercise and would get a negative number, which is the same as doing it the way thats been suggested here, just its a negative not a positive number.
TDEE is BMR+exercise calories. Therefore the number of calories you would eat would ideally be less than that number. So my equation is the same, I'm just totting it up at the end of the day for an exact amount, rather than guessing. Eg, BMR of 1700+exercise of 1200kcals=TDEE of 2900. 2900 - food consumed 1800kcals (more then BMR but less then TDEE) = 1100 (deficit for the day). Now, my equation is this; 1800 (food consumed) - 1700 (BMR) = 100. 100-1200kcals (exercise) = -1100kcals, which is exactly the same deficit!

With just roughly eating less than the TDEE, is just guessing and I dont like that. As I'm a "write everything down" sort of person, I like to know more exact numbers. My way is just easier for me to get my head around. Plus, it gives a negative number, which in my mind, just confirms that I'm in a deficit.

Actually, no. You are still wrong with all your math, and are still creating a bigger deficit than you think.
BMR is functions related to life, not growing hair or nails or fighting off disease, not making improvements to muscle or tendons or ligaments from exercise, ect. It is the most basic functions, with the major energy use being expended on water levels in the cells, then heart and brain function.

TDEE is NOT BMR + exercise calories all by itself. So that assumption throws your math off - and shows why you should NOT start from the bottom up. You should start from the top down if you want to do the TDEE Deficit method.
Otherwise, make it simple on yourself, pick correct MFP activity level, reasonable weight loss goal creating realistic deficit daily, and log and eat back your exercise calories.

Total Daily Energy Expenditure (TDEE) = Basal Metabolic Rate (BMR) + Thermal Effect of Food (TEF) + Non-Exercise Activity Thermogenesis (NEAT) + Exercise Activity Thermogenesis (EAT)

And if you think you are getting exact numbers, you got a surprise coming to you.

You can use that spreadsheet I linked to get best estimates of everything, and you can improve that with an actual bodyfat test and RMR test when you have not been undereating for any time.

But even starting with those great foundations, unless you weigh all your food, and the labels were not allowed to have 5% accuracy, and your cardio exercise was done with gas-exchange mask and metabolic cart, and your lifting was done in thermal capture room where you stayed for 24-36 hrs post workout to catch increase in metabolism - you are no where near the exact numbers you might think you are.

But your math sadly is far removed from exact even given what you can know.

Also rather convoluted if you merely want to estimate what the deficit ended up being on a certain day.

Here's another one for you to throw your math off even further:
Did you know that all reported calories burns from HRM, machine, or database entries like MFP, is NOT the NET calories burned during that time, but rather the GROSS calories burned. Because during that hr of exercise, you were going to burn some calories anyway. If asleep, BMR, if awake, RMR, if moving around, even more. So those reported calories is not just the additional that you burned, but includes what you would have burned anyway.

Since you love numbers, you really should check out the spreadsheet then.

http://www.myfitnesspal.com/topics/show/813720-spreadsheet-bmr-tdee-deficit-macro-calcs-hrm-zones