Calorie Intake vs. Calorie Expenditure?

Hi All! I am new here at MFP and have my personal weight/calorie information entered based on the basic height/weight/general daily activities calculations of the MFP program. Based on my stats I was told I should consume 1,320 calories per day to reach my weight goal. I am trying to figure out how to make my calorie intake the most accurate number possible according to my daily caloric expenditure. In order to get a base line I wore my heart rate monitor (HRM) all day today. I separated the basic calories burned doing my day to day routine from the calories I burned during times of more intense exercise. This is what I found:

Calories burned during normal daytime activities: 1,881
Calories burned during exercise activities: 188-30 min. chain sawing ( I expect this number to vary considerably from day to day)
Total calories burned today: 2,069

So, now my question is if I actually burn 1,881+/- calories a day doing essentially nothing (and more when I devote time to exercise) how many calories should I intake for a healthy weight loss plan? I assume if I eat equal calories to what I burn I will stay at the same weight but is that wrong? Will I actually gain weight if my calorie intake = calories burned? If so, how much difference should there be between what goes in and what gets burned? If I burn 1,881 is it really a big drop to only intake 1,320 (MFP recommendation) or should I readjust that to be a more reasonable number?

I would love some educated advise on this as I feel like I am just guessing here and need to know numbers that A) accurately represent my lifestyle and will safely and healthfully allow me to achieve and maintain my goals.

Thanks!