Looking for calorie advice/help

LadyOdd

I'm brand new to fitbit. Just got it yesterday. I have it synced to mfp, but I am curious about the calories. I have been off and on mfp for a few years now. I believed that the calorie goal was set to lose weight even if I was not very active. I had previously lost 50 lbs just by sticking to the calorie goal, very little exercise. Mfp has my calorie goal at 1800. Fitbit seems to be much lower, as today it is telling me I only have 1055 calories available to be in the zone. I am confused how this works. Should I stick to my usual 1800/slightly under or only have the 1055. Any help would be appreciated.