Harris-Benedict Calculator
A 32-year-old woman weighing 68 kg at 165 cm has an estimated BMR of about 1,449 calories a day and a TDEE near 2,246 calories with moderate activity. This Harris-Benedict calculator uses the revised 1984 Harris-Benedict equation and standard activity multipliers to estimate basal metabolic rate and total daily energy expenditure from age, sex, height, weight, and routine activity.
Quick answer
BMR estimates the calories your body uses at complete rest.
What this tells you
- •BMR estimates the calories your body uses at complete rest.
- •TDEE scales BMR by an activity factor to estimate full-day energy use.
- •This tool uses the revised Harris-Benedict equation published in 1984.
- •The result is a planning estimate, not a diagnosis or prescription.
How to Use
- 1Enter your sex, age, current weight, and current height.
- 2Choose the activity level that best matches your average week, not your hardest day.
- 3Calculate to see estimated BMR, TDEE, and the activity factor used.
- 4Use the result as a starting point, then adjust with real weight and intake tracking.
How It Works
Formula
Men: BMR = 88.362 + 13.397W + 4.799H - 5.677A
Women: BMR = 447.593 + 9.247W + 3.098H - 4.330A
TDEE = BMR x activity factor
Factors used here: sedentary 1.2, light 1.375, moderate 1.55, very 1.725, extra 1.9W is weight in kilograms, H is height in centimeters, and A is age in years. This tool uses the revised Harris-Benedict equation from Roza and Shizgal in 1984, then applies a standard activity multiplier to estimate TDEE.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Moderately active female example
The revised Harris-Benedict formula gives the resting estimate first, then the 1.55 activity factor scales it to a full-day estimate.
Sedentary male example
A lower activity factor keeps TDEE closer to BMR, which is common when structured exercise and daily movement are limited.
Common mistakes
- Choosing an activity level from your best workout week instead of your usual routine
- Entering pounds as kilograms or inches as centimeters
- Treating an estimated TDEE as an exact calorie prescription
Limitations
This calculator uses population-level averages. It does not account for body-fat percentage, muscle mass, pregnancy, menopause, illness, thyroid conditions, medications, adaptive thermogenesis, or changes in step count and training load. Actual maintenance calories can land above or below the estimate.