Calorie counter

I am fairly new to caring about calories...in other words I have only been taking care of myself in a healthy way for about 2 months now...

So what calorie counter do you use? I like the one on here but when I happened to double check on other sites there are of course discrepancies... I am more concerned about calories burned..

I do biking and walking for cardio, also strength and weight training with a trainer...

My concern is to not think I am burning more than I am...I get so confused on words like vigorous and moderate...etc