How calorie needs are estimated

Resting energy comes from a fitted equation

Mifflin-St Jeor estimates resting energy from weight, height, age, and sex. It replaced older equations because it fit modern measurement data better on average.

Activity factors are the roughest input

Multiplying BMR by 1.2 to 1.9 converts resting energy into a daily total. People commonly overestimate their activity level, which inflates the result.

Where the estimate ends

Body composition, medical conditions, medications, and pregnancy shift real needs away from the average. Federal dietary guidance pairs calorie ranges with food quality, not numbers alone.

Boundary: the calculator estimates maintenance energy for healthy adults. Diet planning for medical goals belongs with a clinician or registered dietitian.