Conflicting BMR/RMRs?

feydruss

MFP believes that I'm burning around 1970/day WITH light activity (i.e. BMR + Harris-Benedict equation).

But when I go to other calculators I get 2144, 2010, 2001...

And with this more precise calculator
http://www.health-calc.com/diet/energy-expenditure-advanced
I get over 3000 if I estimate my activity for the average day.

I put down "light" activity and then log my workouts on top of that. I figure I'm "light" because I'm the mother of 10 month old twins, so there's a fair amount of lifting/carrying/squatting/walking/etc in my day.

What's correct? And no, I don't have a HRM.