Bodyweight / 2.2 = __(A)___ A=kilograms
(A) x 24hrs = __(B)__ B=RMR (Resting Metabolic Rate)
(B) x .06 = __(C)__ (calories used for digestion)
(B) x one of the following factors:
.30 for weight training or slower metabolisms
.40 for weight training + cardio training or faster metabolisms
.50 for endurance type training
If I use myself as an example here, my formula would look like this:
180 / 2.2 = 81.82 kilograms
81.82 x 24(hrs) = 1,963 (which is my RMR)
1,963 x .06 = 117.82
1,963 x .30 (I do cardio also but I have a slow metabolism) = 588.90
Now let's add them up 1,963+117.82+588.90 = 2,669.72 (round up to 2,700) calories per day.

After you find out how many calories you need to maintain your weight, start cutting back 100 calories a week until you notice fat loss. Don't go too low. You should be losing 1 pound a week. If you start losing more than 1 pound every week, it is possible some of that weight is muscle. Don't go below 2200 calories. I always keep a balanced diet: 60% of calories are from carbs; 25% are from protein; 15% from fat. Even when I cut I use this ratio. But most people like to lower their carb intake and increase their protein and fat intake. If you want to do this, I recommend this ratio: 40% carbs/40% protein/20% fat. This will work. Good luck. Also do 3 cardio sessions per week for 20-30 minutes.

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Give me the wisdom to know what is right
And give me the courage to do what is right