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!
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.