BMR Calculator
Estimate your basal metabolic rate (BMR) and total daily energy expenditure (TDEE) to see roughly how many calories your body uses each day
Your Metrics
Your Energy Expenditure
The number of calories your body burns at rest just to keep you alive (breathing, circulating blood, cell production).
An estimate of your maintenance calories. Actual needs vary from person to person and over time.
How to use this tool
- Choose Metric (kg, cm) or Imperial (lbs, ft) and select Male or Female.
- Enter your age, height and weight.
- Pick the activity level that best matches a typical week.
- Read the Basal Metabolic Rate (BMR) and the Total Daily Energy Expenditure (TDEE), a maintenance estimate.
Worked example
A 30-year-old man who is 175 cm tall and weighs 70 kg gets BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 kcal/day with the Mifflin-St Jeor equation. At a moderately active level (×1.55) the TDEE is about 2,556 kcal/day. For a 28-year-old woman of 165 cm and 60 kg the equation ends in −161 instead of +5: 600 + 1,031.25 − 140 − 161 ≈ 1,330 kcal/day, and about 2,062 kcal/day at the same activity level. These are population-average estimates, not a diet prescription; for weight goals or health conditions, consult a qualified professional.
Why this tool exists and where its numbers come from
People planning food or training want a starting estimate of resting energy use. The tool uses the Mifflin–St Jeor equation, derived from 498 healthy adults; the activity multipliers added on top are conventional, and the result is an estimate, not a prescription.
Sources
- Mifflin et al., Am J Clin Nutr 1990 (PubMed abstract)
- Frankenfield, Roth-Yousey & Compher, J Am Diet Assoc 2005 (systematic review, PubMed abstract)
For the full method, see the Methodology section just below.
Methodology
This tool uses the Mifflin-St Jeor equation, published by Mifflin, St Jeor et al. in the American Journal of Clinical Nutrition (1990). A 2005 systematic review in the Journal of the American Dietetic Association (Frankenfield, Roth-Yousey and Compher; the association is now the Academy of Nutrition and Dietetics) found it the most reliable of the common equations: the one most likely to estimate measured resting metabolic rate to within 10%, though with noteworthy errors for individuals.
Mifflin-St Jeor results for six everyday profiles
These are the values the calculator returns for six sample profiles, in kcal/day, with TDEE shown at the sedentary (×1.2) and moderately active (×1.55) levels. TDEE is rounded from the unrounded BMR.
| Profile | BMR | TDEE ×1.2 | TDEE ×1.55 |
|---|---|---|---|
| Male, 25 y, 180 cm, 75 kg | 1,755 | 2,106 | 2,720 |
| Male, 45 y, 175 cm, 85 kg | 1,724 | 2,069 | 2,672 |
| Male, 60 y, 170 cm, 78 kg | 1,548 | 1,857 | 2,399 |
| Female, 25 y, 165 cm, 58 kg | 1,325 | 1,590 | 2,054 |
| Female, 45 y, 165 cm, 70 kg | 1,345 | 1,614 | 2,085 |
| Female, 60 y, 160 cm, 65 kg | 1,189 | 1,427 | 1,843 |
How to read it: age costs 5 kcal per year, so each decade lowers BMR by about 50 kcal, while every extra kilogram adds 10 and every centimeter 6.25. The big swing in TDEE comes from the activity level, roughly 610 kcal between the two columns for the first profile, which is why choosing the multiplier honestly matters. These are population-average estimates for healthy adults, not medical or nutritional advice.
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Frequently asked questions
What is the difference between BMR and TDEE? ▼
BMR (basal metabolic rate) is the minimum number of calories your body needs at rest to keep its organs, breathing and brain working. TDEE (total daily energy expenditure) adds the calories you burn through daily movement and exercise. TDEE is the number to use when you plan what you eat.
Is the Mifflin-St Jeor equation better than Harris-Benedict? ▼
Validation studies have generally found Mifflin-St Jeor predicts resting energy expenditure within 10% for more people than the Harris-Benedict equation (1919). Both are estimates, and individual results vary.
Should I eat below my BMR to lose weight? ▼
Many guidelines advise against going below your BMR for long and describe moderate deficits taken from TDEE rather than from BMR. The right target depends on your health and goals, so ask a doctor or registered dietitian before changing your intake.
Can you show a worked example of the numbers? ▼
For a 35-year-old man, 80 kg and 180 cm, the equation gives 10 × 80 + 6.25 × 180 − 5 × 35 + 5 = 1,755 kcal per day at rest. With the default activity factor of 1.55 (moderately active), TDEE is about 2,720 kcal. For a 30-year-old woman, 65 kg and 165 cm, BMR is 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = about 1,370 kcal, and about 2,124 kcal at 1.55. Pounds are divided by 2.20462 and feet and inches converted to centimeters before the formula is applied.
How reliable is the activity multiplier, and when does the tool show 0? ▼
The factors 1.2, 1.375, 1.55, 1.725 and 1.9 are conventional approximations, not measurements of your own movement. People often overestimate how active they are, which inflates TDEE by several hundred kcal, so choosing the lower neighboring level is a common sanity check. The tool shows 0 when age, weight or height is missing or zero, or when the equation would give a non-positive value. The equation was built for healthy adults and is not meant for children, pregnancy or medical conditions, where a clinician should advise instead.