Guides

Every calculator here explains its method on the tool page itself. These guides go one step further: they compare formulas, put the studies in context, and show where an estimate ends and a measurement begins. Every text cites its sources.

• Mifflin–St Jeor vs Harris–Benedict vs Katch–McArdle: which BMR formula should you use?
  The three common resting-metabolism formulas, side by side with a worked example, what the validation studies found, and when body-fat-based formulas win.