TDEE Calculator: Estimate Your Daily Calories With Mifflin-St Jeor
A TDEE calculator estimates total daily energy expenditure by multiplying resting energy from the Mifflin-St Jeor equation by an activity factor.[1] For an 80 kg, 180 cm, 35-year-old man, resting energy is 1,755 kcal, and at a moderate factor of 1.55 the estimate is about 2,720 kcal per day. It is an estimate, not a measurement, and this page shows every step.
TDEE calculator
Estimate from the Mifflin-St Jeor equation and a conventional activity multiplier. Real needs vary. This is not a calorie target.
What is TDEE?
TDEE stands for total daily energy expenditure, the energy your body uses in a day, counted in kilocalories (kcal). It has two main parts: resting energy, the amount you burn to stay alive at rest, and the extra energy from movement and exercise. A calculator cannot measure either one. It estimates resting energy from your weight, height, age, and sex with a prediction equation, then scales that figure by an activity factor. The Mifflin-St Jeor equation was derived from 498 healthy adults whose resting energy expenditure was measured by indirect calorimetry.[1] The result is a single daily number that people often call maintenance calories. Real expenditure varies from person to person and from week to week, so treat the output as a starting estimate you can compare with your own records, not as a target you must eat.
How do you calculate TDEE with the Mifflin-St Jeor equation?
Work out resting energy first, then multiply. The 1990 paper by Mifflin and colleagues gives two equations: for males, 10 x weight in kg + 6.25 x height in cm - 5 x age in years + 5, and for females, the same terms with 161 subtracted instead of 5 added.[1] Take a man who is 80 kg, 180 cm, and 35 years old. That is 800 + 1,125 - 175 + 5, or 1,755 kcal. At the moderate factor of 1.55, 1,755 x 1.55 is 2,720.25, which the tool rounds to 2,720 kcal. Now take a woman who is 68 kg, 165 cm, and 45 years old. That is 680 + 1,031.25 - 225 - 161, or 1,325.25 kcal. At a light factor of 1.375 the estimate is 1,822 kcal. The calculator below runs these steps for the values you enter.
| Sex | Equation | Example |
|---|---|---|
| Male | 10 x kg + 6.25 x cm - 5 x age + 5 | 80 kg, 180 cm, 35 y: 1,755 kcal |
| Female | 10 x kg + 6.25 x cm - 5 x age - 161 | 68 kg, 165 cm, 45 y: 1,325.25 kcal |
What is the difference between BMR and TDEE?
BMR, or basal metabolic rate, is the energy used at complete rest. The Mifflin-St Jeor paper measured the closely related resting energy expenditure and called it REE.[1] TDEE is the whole day, including movement. The factor that links them is the physical activity level, or PAL, which the FAO, WHO and United Nations University report defines as average 24-hour total energy expenditure divided by BMR.[3] So TDEE equals BMR times PAL. In the 80 kg example, a BMR of 1,755 kcal and a PAL of 1.55 gives 2,720 kcal. The tool shows both numbers, labeled BMR at rest and the maintenance estimate, so you can see how much of the total is resting energy and how much comes from your activity choice. At a PAL of 1.2 the same BMR gives 2,106 kcal, which is 614 kcal below the 1.55 result.
Which activity multiplier should you choose?
Pick the level that matches a typical week, not your best week. PepTrac uses six conventional multipliers: sedentary 1.2, lightly active 1.375, moderately active 1.55, very active 1.725, extra active 1.9, and a top tier of 2.0 that is PepTrac's own. They are a widely used convention, and PepTrac does not claim a single paper sets them. The FAO, WHO and United Nations University report groups lifestyles into bands of physical activity level instead: 1.40 to 1.69 for sedentary or light, 1.70 to 1.99 for active or moderate, and 2.00 to 2.40 for vigorous, with values above 2.40 hard to maintain for long.[3] If you are unsure between two levels, compare both results and notice how close they are. In the table below, each step between the first five levels changes the estimate by about 307 kcal, so the choice matters.
| Activity level | Factor | Estimate |
|---|---|---|
| Sedentary | 1.2 | 2,106 kcal |
| Lightly active | 1.375 | 2,413 kcal |
| Moderately active | 1.55 | 2,720 kcal |
| Very active | 1.725 | 3,027 kcal |
| Extra active | 1.9 | 3,335 kcal |
| Extreme (PepTrac top tier) | 2.0 | 3,510 kcal |
| Lifestyle | PAL range |
|---|---|
| Sedentary or light activity | 1.40 to 1.69 |
| Active or moderately active | 1.70 to 1.99 |
| Vigorous | 2.00 to 2.40 |
How accurate is the Mifflin-St Jeor equation?
It is accurate enough for a first estimate, but not exact for any one person. The 1990 equation was fitted to 498 healthy adults, aged 19 to 78, and explained 71% of the variation in measured resting energy (R squared of 0.71).[1] In the same data, the older Harris-Benedict equations, from 1919, overestimated measured resting energy by 5%.[1] A 2005 systematic review by Frankenfield and colleagues compared common equations and found Mifflin-St Jeor the most reliable, predicting resting metabolic rate within 10% of measured in more people than the others. The same review warned of noteworthy errors for individuals, and said older adults and US-residing ethnic minorities were underrepresented in the studies.[2] For scale, 10% of the 1,755 kcal resting example is about 176 kcal, before the activity step adds its own uncertainty. Indirect calorimetry, which measures resting metabolic rate directly, is the way to remove the equation error.[2]
Does TDEE change as you lose weight?
Yes, because weight is an input. In the Mifflin-St Jeor equation, each kilogram adds 10 kcal to resting energy.[1] Take a 52-year-old woman who is 95 kg and 170 cm. Her resting energy is 950 + 1,062.5 - 260 - 161, or 1,591.5 kcal, and at a sedentary factor of 1.2 her estimate is 1,910 kcal. At 85 kg her resting energy is 1,491.5 kcal and her estimate is 1,790 kcal. A 10 kg change lowers the estimate by 120 kcal a day, which is 10 kg x 10 kcal of resting energy, times the 1.2 factor. Because the answer depends on your current weight, an estimate made months ago goes out of date. Recalculate when your weight or your activity changes meaningfully. The tool then shows resting energy and the maintenance estimate for your new weight.
How does TDEE relate to GLP-1 therapy?
TDEE is the energy you burn, which is different from the energy you eat, and the gap matters on GLP-1 medicines such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).[5][6][7][8] A 2025 joint advisory from four nutrition and obesity societies reports energy intake reductions of 16% to 39% with GLP-1 medications.[4] If intake started equal to the 2,720 kcal example estimate, that range would be 435 to 1,061 kcal less food, which is arithmetic and not a goal. The advisory also says nutrient shortfalls are a concern, especially at energy intakes below 1,200 kcal a day for females and below 1,800 kcal a day for males.[4] This page does not recommend a calorie target or a deficit. The tool shows an estimate and two plain offsets, 500 kcal below and 300 kcal above, as arithmetic only, not as goals. A prescriber or registered dietitian can set an intake that fits your treatment, your size, and your health.
Frequently asked questions
Is TDEE the same as maintenance calories?
In everyday use, yes. Both mean the estimated energy needed to hold your weight steady. It is an estimate from an equation and an activity factor, so your own weight trend over several weeks is the better check.
How many calories should I eat on Ozempic, Wegovy, Mounjaro or Zepbound?
This page does not set a calorie target. The 2025 joint advisory warns that nutrient shortfalls are a concern below 1,200 kcal a day for females and 1,800 kcal a day for males. A prescriber or registered dietitian can set an intake for you.
Why does the calculator ask for sex?
The Mifflin-St Jeor equation has different constants: plus 5 for males and minus 161 for females. The tool also offers prefer not to say, which uses a midpoint offset of minus 78. That midpoint is PepTrac's own choice, not a published value.
Should I eat my TDEE?
This tool does not advise an intake. TDEE is an estimate of what you burn, not a recommendation for what to eat. A clinician or registered dietitian can help set an intake that fits your goals, your health, and any medication.
How often should I recalculate my TDEE?
Recalculate when your weight or your usual activity changes in a meaningful way. Each kilogram changes resting energy by 10 kcal in the equation, so a large weight change moves the estimate. Small day to day swings do not matter.
Why do other TDEE calculators give a different number?
Some use older equations such as Harris-Benedict, which overestimated measured resting energy by 5% in the Mifflin-St Jeor study data. Others use different activity multipliers. Compare the equation and the factor, not just the final number.
Does PepTrac measure the calories I burn?
PepTrac reads steps and calories burned from Apple Health on iPhone, and it logs food and weight. This calculator is a separate estimate. PepTrac is free to download, with an optional PepTrac Pro, and it is not medical advice.
Sources
- The American Journal of Clinical Nutrition. A new predictive equation for resting energy expenditure in healthy individuals (Mifflin et al., 1990). Accessed October 3, 2026.
- Journal of the American Dietetic Association. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review (Frankenfield et al., 2005). Accessed October 3, 2026.
- Food and Agriculture Organization of the United Nations (FAO/WHO/UNU). Human Energy Requirements, chapter 5 (FAO/WHO/UNU expert consultation, 2004). Accessed October 3, 2026.
- American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, The Obesity Society (Obesity, 2025). Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Novo Nordisk). Ozempic (semaglutide) injection prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Novo Nordisk). Wegovy (semaglutide) prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Eli Lilly). Mounjaro (tirzepatide) injection prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Eli Lilly). Zepbound (tirzepatide) prescribing information. Accessed October 3, 2026.
Written and maintained by the team that builds PepTrac. Every calculator on this site runs the same tested math as the app. Read how we research, cite, and update pages in our editorial policy.
