You probably won't get anything really accurate unless you go to the doctor for a special test, since your body is unique. The online calculators are based on forumulas which are just a starting point to give you a general idea of what most people like you will burn. I watched a tv show on FitTv recently and they showed several people get tested. The basic calculators may say you burn about 2600 (as an example) calories to maintain yourself, but one woman they showed had a very slow metabolism and only burned 1200 calories per day. Everyone was different. It was hard to reduce her calories by very much, so they worked on increasing her metabolism by adding more exercise, and she lost weight. But that's another topic
Have you ever kept a food log even when not dieting to lose? It might help to know how many calories you can eat while maintaining your weight.
You might even pick a number and see how it works for you, then tweak it as needed. A lot of our members lose well at 1600 calories, some need 1200.
Good luck
