The TDEE formula, step by step
TDEE = BMR × activity factor. Every equation written out, with the same person run through each one.
The TDEE formula has two parts. A resting equation estimates your basal metabolic rate from sex, age, height and weight (or from lean mass). A multiplier scales it up for how much you move. All the formulas below are run for the same man: 30 years old, 5 ft 9 in (175.3 cm), 176 lb (79.8 kg), moderately active (× 1.55).
Mifflin-St Jeor (1990), the default
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Example: 10 × 79.8 kg + 6.25 × 175.3 cm − 5 × 30 + 5 = 1,749 kcal. TDEE = 1,749 × 1.55 = 2,710 kcal/day.
Published in 1990 from measurements of 498 adults, and the equation that predicted measured resting metabolism most reliably in a later systematic review. It needs no body-fat estimate, which is why it is the default on this site and on most others.
Harris-Benedict, revised by Roza and Shizgal (1984)
Men: BMR = 88.362 + 13.397 × weight (kg) + 4.799 × height (cm) − 5.677 × age
Women: BMR = 447.593 + 9.247 × weight (kg) + 3.098 × height (cm) − 4.330 × age
Example: 88.362 + 13.397 × 79.8 + 4.799 × 175.3 − 5.677 × 30 = 1,829 kcal. TDEE = 2,834 kcal/day.
The original 1919 equation tended to overestimate; the 1984 revision reduced that. It still runs a little higher than Mifflin-St Jeor for most people, which is the main reason older calculators give bigger numbers.
Katch-McArdle, from lean mass
BMR = 370 + 21.6 × lean body mass (kg)
lean body mass = weight × (1 − body fat %)
Example at 20% body fat: lean mass = 79.8 × 0.80 = 63.9 kg; BMR = 370 + 21.6 × 63.9 = 1,750 kcal; TDEE = 2,712 kcal/day.
Ignores sex and age entirely, because lean tissue is what burns energy at rest. The catch is the input: a body-fat percentage guessed from a mirror or a bathroom scale can be off by 5 to 10 points, and each point moves BMR by about 17 kcal. Best used with a measured value (DEXA, a skilled caliper reading).
Cunningham (1980), from lean mass
BMR = 500 + 22 × lean body mass (kg)
Example at 20% body fat: 500 + 22 × 63.9 = 1,905 kcal; TDEE = 2,953 kcal/day.
Built on a reanalysis of the Harris-Benedict data and popular in sports nutrition because it runs higher for lean, muscular people. Same dependence on a good body-fat number as Katch-McArdle.
The activity multipliers
| Level | Factor | Example TDEE (BMR 1,749) |
|---|---|---|
| Sedentary | × 1.2 | 2,098 kcal |
| Lightly active | × 1.375 | 2,404 kcal |
| Moderately active | × 1.55 | 2,710 kcal |
| Very active | × 1.725 | 3,017 kcal |
| Extra active | × 1.9 | 3,323 kcal |
These five numbers are a convention that grew out of the Harris-Benedict tradition rather than a single study; they already include the energy cost of digesting food. Choosing between them is covered on the activity level page, and the gaps between formulas are covered on the accuracy page.
Which formula should you use?
- Most people: Mifflin-St Jeor. Best validated, no body-fat input, and the number the calculator on this site shows first.
- You know your body fat from a real measurement: look at Katch-McArdle as well; if you are lean and muscular it will be higher than Mifflin, and that is probably closer to the truth.
- You are comparing with an older calculator: it likely used Harris-Benedict; expect it to run 3 to 5% higher.
- You have logged weight and intake for three weeks: use none of them. Your observed TDEE from the tracker beats every formula.
Questions
What is the TDEE equation in pounds and inches?
Convert first: kilograms = pounds × 0.4536, centimeters = inches × 2.54. Then apply Mifflin-St Jeor. Written directly in US units the men's equation becomes 4.536 × lb + 15.875 × in − 5 × age + 5, but rounding the coefficients is what causes small differences between sites, so converting the inputs is cleaner.
How do I calculate TDEE from BMR?
Multiply BMR by the activity factor: 1.2 if you are sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active. A BMR of 1,700 at 1.375 is a TDEE of 2,338 kcal.
What is the Mifflin-St Jeor equation calorie calculator?
Any calorie calculator whose resting equation is 10 × kg + 6.25 × cm − 5 × age, plus 5 for men or minus 161 for women. The calculator on this site is one, and it shows the equation filled in with your numbers so you can verify it.
By Alton Vieira · Updated . Estimates for healthy adults; not medical advice. How every number is calculated.
- Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990.
- Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. Am J Clin Nutr. 1984.
- McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy, and Human Performance. Lippincott Williams & Wilkins (textbook).
- Cunningham JJ. A reanalysis of the factors influencing basal metabolic rate in normal adults. Am J Clin Nutr. 1980.
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005.