You're right - there are multiple websites that give estimates of your recommended calorie intake based upon height and weight, depending on specific approximations of how many calories you burn in a day. Your height, weight, age, and sex might provide a decent estimate of your basal metabolic rate (what you burn while doing nothing), but people's activity levels have such a broad range that it is difficult to provide great estimates. In my opinion, it's a better practice to target nutrition (increasing fiber, lowering salt, getting healthy fats from fish and nuts) rather than calories alone.
It's all so confusing, why can't losing weight be more simple? I remember when I lost 80 lbs, it was when ephedra came on the market and it was EASY because I had the energy to work out and the pounds melted away and I wasn't hungry all of the time. Now, I have no energy, I'm in my late 30's and taking off weight is like pulling an elephant with a rope! :o( It can be so discouraging!