Check out IIFYM. If it fits your macros.
You will find a ton of information about how to count your calorie requirements, deductions etc.
A simple way is to use this site, if it has not already been posted before -http://www.freedieting.com/tools/calorie_calculator.htm
Throw in your details and you will get a number for cutting/bulking or maintaining.
Now as you probably already know some calculators are not always right. It does not take it the metabolism rate of people
and to some hard exercise would be different to another.
Once you receive these numbers stay on top of them for a week or two and see what happens to your body.
It's always trial and error with dieting. No one is the same.
Basic Macros =
1 gram of fat = 9 calories
1 gram of pro = 4 calories
1 gram of carbs - 4 calories
We'll use my body weight as an example. I am 80kg/176lbs.
My weight to cut according to the calculator is 2108 calories.
A rule of thumb for protein is 1-1.2g of protein per pound of bodyweight. So 176lbsx1.2g = 211.2g
So 211.2g of protein x 4calories = 844.8cals for Protein.
A rule of thumb for fat is a minimum of 0.5g per pound of bodyweight. So 176lbsx0.5g = 88g
So 88g of fat x 9calories = 792 calories.
Ok so now you have 792calories of fat and 844.8calores of protein. Add them together you get 1636,8 calories.
Remember I have 2108 calories to cut with. 2108 (total) - 1636.8 (pro+fat) = 471.2 calories left over.
Those left over calories would be your carbs.
So 471.2 devinde by 4 calories = 117.8g of carbs.
So my end totals add up to - Calories 2108, Protein: 211.2g, Fat:88g, Carbs:117.8g.
That's what I need to cut each week.
Also I recommend as I have been told to have 10-14g of fibre per 1000 calories.
Sorry if it's a bit rushed its very late here and I have work in the morning
I'm sure you will find great info from a lot of people on this forum. I've just stuck to this formula as many people I know have and it;s worked wonders.