Harris-Benedict Calculator
Calculate your BMR with the revised Harris-Benedict equation and your TDEE by activity level. Inputs are sex, age, height, and weight.
By Jonas Lindemann · Updated · How we build our calculators
2751kcal/day
maintenance calories (TDEE)
1775
BMR (kcal/day)
×1.55
activity factor
Note: The revised Harris-Benedict equation estimates resting metabolism. Actual needs vary with body composition and genetics. This is general guidance, not medical advice.
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Calculation Method
The Harris-Benedict equation is one of the original and most widely used ways to estimate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest just to stay alive. Multiply BMR by an activity factor and you get your Total Daily Energy Expenditure (TDEE), the maintenance calorie level around which all diet planning revolves.
The Formula (Revised)
We use the 1984 Roza & Shizgal revision, which is more accurate than the 1919 original. BMR is in kcal/day from weight (kg), height (cm), and age (years).
Women: BMR = 447.593 + 9.247×kg + 3.098×cm − 4.330×age
TDEE = BMR × activityFactor
Worked Example
A 30-year-old man, 75 kg, 178 cm, moderately active:
- BMR = 88.362 + 13.397×75 + 4.799×178 − 5.677×30
- = 88.362 + 1004.8 + 854.2 − 170.3 = 1,777 kcal
- TDEE = 1,777 × 1.55 ≈ 2,754 kcal/day
Activity Multipliers
| Activity level | Factor |
|---|---|
| Sedentary (little/no exercise) | 1.20 |
| Light (1-3 days/week) | 1.375 |
| Moderate (3-5 days/week) | 1.55 |
| Active (6-7 days/week) | 1.725 |
| Very active (hard daily) | 1.90 |
Harris-Benedict vs Mifflin-St Jeor
Harris-Benedict tends to estimate BMR a little higher than the newer Mifflin-St Jeor equation, especially for people with higher body fat. Both are population averages built from height, weight, and age; neither accounts for body composition. If you know your body-fat percentage, the Katch-McArdle equation may suit you better.
Using Your TDEE
- Maintain: eat at TDEE.
- Lose fat: subtract 300-500 kcal/day for roughly 0.3-0.5 kg/week.
- Gain muscle: add 200-400 kcal/day with adequate protein.
Note: This is an estimate of energy needs, not a medical assessment. Actual metabolism varies with genetics, hormones, and body composition. Track your weight for 2-3 weeks and adjust calories to match reality.
Frequently Asked Questions
It is a classic formula for estimating Basal Metabolic Rate from weight, height, age, and sex. Multiplying BMR by an activity factor gives your Total Daily Energy Expenditure (TDEE).
The revised version is reasonably accurate for most people but tends to estimate slightly higher than Mifflin-St Jeor, especially at higher body fat. It is a starting estimate, not an exact figure.
Mifflin-St Jeor is often considered marginally more accurate for the general population, while Harris-Benedict is the historical standard. If you know your body fat, Katch-McArdle may suit you best.
Eat at TDEE to maintain. Subtract 300-500 kcal/day to lose roughly 0.3-0.5 kg/week, or add 200-400 kcal/day with adequate protein to gain muscle.