To add to what Samuel_Michon wrote, I'm 38, 103kg at the moment (I'm substantially above averagely muscular, but also somewhat overweight now), 1m 85, and I exercise hard 5 days a week - 1 hour of heavy weights 3-4 times/week, and cardio the rest. I work in an office, so my work day is fairly sedentary. I also have a young son which keeps me more active than I've ever been before during the evenings.
I burn ~2800 kcal/day when I exercise.
This is an estimate based on tracking every meal, and tracking my weight every morning, rather than what I "should" be burning.
Unless you have a very active job, or exercise hard (think stumbling out of the gym) for substantially more than an hour a day, or spend every moment of your spare time being highly active, you're likely not burning 3400 calories.
But really, write down what you eat for a couple of weeks, count the calories, track your weight, then adjust the number of calories to target up/down depending on whether you want to increase/decrease your weight, as there are so many factors that can change what how much you need.