just google for 'harris benedict bmr calculation'
you'll need to convert height and weight to metric.
and since you're 138% of your "ideal" bodyweight, the BMR value you're gonna get will be on the high side. I'd drop 200cals from the BMR before you multiply it by your activity level.
And even then, real life daily intake for 2 weeks, and then seeing if you lost bodyfat, or maintained, is the better way.
Calculations only get you an estimate.
