Health

Calorie Calculator

Estimate how many calories you need per day from age, sex, weight, height, and activity — starting with Mifflin–St Jeor BMR, then multiplying by an activity factor for TDEE.

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Result

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The formula

Mifflin–St Jeor estimates basal metabolic rate (BMR) from weight (kg), height (cm), age, and sex. Total daily energy expenditure (TDEE) multiplies BMR by an activity factor. Treat the result as a starting estimate and adjust from real-world weight and energy trends.

BMR (male) = 10×kg + 6.25×cm − 5×age + 5; BMR (female) = 10×kg + 6.25×cm − 5×age − 161

Worked example

  1. Male, 30 yrs, 75 kg, 178 cm, moderate activity (×1.55)
  2. BMR ≈ 10×75 + 6.25×178 − 5×30 + 5 = 1,738 kcal
  3. TDEE ≈ 1,738 × 1.55 ≈ 2,694 kcal

Result: ≈ 2,694 kcal/day estimated TDEE

How calorie needs are estimated

No equation knows your exact metabolism. These formulas approximate resting burn, then scale for activity.

Mifflin–St Jeor BMR

Published in 1990, Mifflin–St Jeor generally outperforms older Harris–Benedict equations for modern adults in validation studies. It predicts resting energy needs, not gym performance.

Sex-specific constants reflect average differences in body composition; they are population averages, not a statement about every individual.

Activity multipliers (TDEE)

Common factors range from ~1.2 (sedentary) to ~1.9 (very high activity). They are coarse buckets. Someone who sits all day but trains hard three evenings may sit between “light” and “moderate.”

Weight goals

A rough heuristic is that ~500 kcal/day below TDEE trends toward gradual loss and ~500 above toward gain — but adaptation, NEAT, water, and adherence matter more than spreadsheet precision. Medical conditions and medications change needs; get clinical advice when relevant.

Limits of food labels

Label calories use Atwater factors and rounding. Laboratory bomb calorimetry can differ. Everyday tracking is approximate by design.

Interesting facts

Mifflin–St Jeor (1990)

The Mifflin–St Jeor equation estimates resting energy needs and is generally more accurate than Harris–Benedict for contemporary adults.

BMR vs TDEE

BMR is energy at complete rest. TDEE multiplies BMR by an activity factor to reflect daily movement and exercise.

Metabolism adapts

Energy burn changes with weight, sleep, illness, and training. Recalculate after large weight changes and watch trends, not single days.

Protein and satiety

At similar calories, higher-protein patterns often help preserve lean mass in a deficit and manage hunger.

Labels are rounded

Food labels use standardized factors. Real metabolizable energy can differ slightly from the printed number.

Frequently asked questions

Total Daily Energy Expenditure — estimated calories burned including activity. Eating below TDEE tends toward loss; above toward gain, all else equal.

Validation work found Mifflin–St Jeor closer to measured resting expenditure for many modern adults. No formula is perfect for every person.

Pick the option that matches most of your week, not your hardest training day. When unsure, start lower and adjust after 2–3 weeks of consistent tracking.

It is a starting point. Muscle mass and training raise needs; scale weight and performance are better feedback than the first estimate alone.

Not as a default. Growth, pregnancy, and medical conditions need clinician-guided targets.

References

  1. A new predictive equation for resting energy expenditure in healthy individuals (Mifflin et al., 1990) — American Journal of Clinical Nutrition Original Mifflin–St Jeor publication.
  2. Dietary Guidelines for Americans — U.S. Department of Agriculture / HHS Population nutrition guidance context for energy balance.
  3. Estimated energy requirements overview — National Institutes of Health (Office of Dietary Supplements / related nutrition resources) US federal nutrition science portal for further reading.