Figure your ACTUAL TDEE without a calculator

We know calculators just give us an estimate right? And ideally we need to use what we get from a calculator as a starting point, then adjust depending on how our bodies react, right?
It's really easy to do. It just takes a little time, consistency and commitment. And hell, we're all committed to our weight loss goal right?

OK. So heres what you do:
1. Figure your TDEE using http://www.fitnessfrog.com/calculators/tdee-calculator.html or whatever website you prefer.
2. Set your daily caloric intake to TDEE - 10% or 20% or whatever your goals are, just never less than 30%).
3. Eat as close as you can to that amount and record it daily for 6 to 8 weeks (the longer the better as far as accuracy).
4. Record your weight weekly or bi-weekly and at the end of the 6 to 8 weeks, compare your beginning and ending weight to determine how much you have lost, or gained.

Now you should have:
a. total calories for 6 weeks (or 8, just using 6 to keep it simple)
b. total weight gained or lost for 6 weeks.

Now you can figure your ACTUAL TDEE and daily caloric requirements using these numbers by recording the following:
X divided by 6= weekly calorie intake (where X = total calories for the 6 weeks), Call this Variable "A"
Y divided by 6= weight lost or gained per week (where Y = total weight loss or gained for the 6 weeks), call this variable "B"

B * 3500= caloric deficit or surplus per week. Divide this number by 7 and it will give you the amount of calories you were over or under maintenance each day. Call this variable "C". If you gained weight express C as a negative number.
To figure your actuall TDEE: A/7 + C = your maintenance.

An example:
Lets say the TDEE calculator says my TDEE is 3000. So I eat at 2400 per day (TDEE - 20%) for 6 weeks and I lose 4 pounds.
So X for me = (2400*7) = 16,800. 16,800 * 6 = 100,800 This is my total calories eaten in 6 weeks. A = 16800
Y for me = 4 4/6 = .67 So I lost .67 pounds per week. B = .67

B * 3500= .67* 3500 = 2345 This is my actual caloric deficit per week, based on the actual weight lost.
So 2345 / 7 = 335 calories per day UNDER maintenance (since I lost weight).
Since I have figured my average daily calories at 2400, I know that if I ate 335 more calories per day, I would be at maintenance.
So the calculator gave me 3000 per day, but my actual TDEE is 2400 + 335 = 2735.

So now If I wanted to up my loss to 1 pound per week as compared to the .67, I would just need to drop .33 more calories per week (or day). So since I am currently at a 335 calorie per day deficit, 335 * 1 .33 = 445. I would need to up my deficit to 445 per day.

Maybe I am making this too complicated, but it works for me. The key is consistency with diet and exercise. However if you miss a day at the gym or miss your calorie goals a day or two a month, it will still average out, and the longer amount of time you use to get your average, the better it will be.

If you have a drastic lifestyle change, it obviously won't work. For example if you decide to stop working out, or drastically change your workout routine. Likewise, extreme diet changes will affect it as well, as your macronutrient composition can drastically change when you totally switch all the foods you eat. Other than that it should work pretty well as you will be measuring YOUR SPECIFIC lifestyle, diet, exercise, etc. and NOT what is given to you via a calculator.

So if you have a cheat day once a week, work out 3 days a week, have a soda twice a week, or whatever. Just stay consistent with it or make small changes at a time.

I know looking at my example it could have been a lot easier as I used a consistent variable (2400) for my daily caloric intake, so I could have skipped some of the math. In reality, I personally have a hard time hitting my calories right on the nose every day, so using these formulas would allow me to get my daily average, when my days are inconsistent (which is most days for me!).

Anyway, hope this helps someone, or if someone has already done this and has a better way, I am all ears. I think I will put this in a spreadsheet to help track it over longer periods of time.