Published in 1990, Mifflin-St Jeor is the BMR formula most widely recommended today for healthy adults. It's the default used throughout this site.
Mifflin-St Jeor estimates BMR from weight, height, age and sex:
When researchers compared the common BMR equations, Mifflin-St Jeor predicted resting energy more accurately than the older Harris-Benedict equation for most people.3 It needs no body-fat measurement, which makes it practical for general use. Its main limitation is the same as any height/weight formula: it can't account for unusual body composition, where a lean-mass-based equation like Katch-McArdle does better.
Formula as published in Mifflin et al., American Journal of Clinical Nutrition, 1990.1 See the methodology & sources page for full references.
For most people, yes — studies have found it predicts resting energy expenditure more accurately than the older Harris-Benedict equation.
No. It uses weight, height, age and sex only. If you have a measured body-fat percentage, Katch-McArdle may be more accurate.