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BMR calculator

Estimate your basal metabolic rate (BMR) and total daily energy expenditure (TDEE) using the Mifflin-St Jeor equation and your activity level.

Required fields are marked with an asterisk (*).

Sex
The equation uses a different constant by sex.
Your age in years.
Your current weight in the chosen unit.
Weight unit
Choose between kilograms and pounds; the calculator converts automatically.
Your height in the chosen unit.
Height unit
Choose between centimetres and metres; the calculator converts automatically.
Choose the option closest to your daily routine: sedentary, light, moderate, active, or very active.

Basal metabolic rate (BMR) is the energy your body burns at complete rest just to stay alive, and total daily energy expenditure (TDEE) adds the effect of your daily activity. This calculator works out both figures using the Mifflin-St Jeor equation and the activity level you choose.

Formula

BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + (5 for male or −161 for female), then TDEE = BMR × activity factor (1.2 / 1.375 / 1.55 / 1.725 / 1.9).

When is this useful?

Use this calculator when planning a diet or training programme, to estimate your daily energy needs as a starting point for your calorie target.

Worked example

Example using the calculator’s values: male, age 30, weight 80 kg, height 180 cm, moderate activity.
BMR is about 1,780 calories/day.
TDEE is about 2,759 calories/day.

Assumptions

  • The calculator uses the Mifflin-St Jeor equation to estimate BMR.
  • TDEE is an estimate computed as BMR times the chosen activity factor.
  • Units are converted automatically when pounds or metres are chosen.
  • Choosing a realistic activity level matters for the result.
  • Estimates are general and are not medical advice or diagnosis.

Common mistakes

  • Choosing an activity level higher than your actual routine, which inflates the figure.
  • Entering weight in pounds without accounting for the conversion to kilograms.
  • Confusing BMR with TDEE: the former is at rest, the latter adds activity.
  • Relying on the result as medical fact instead of treating it as an estimate.

Frequently asked questions

What is the difference between BMR and TDEE?

BMR is what your body burns at complete rest, while TDEE adds the effect of your daily activity and is the figure closest to your actual energy needs.

Why does the calculator ask for sex?

Because the Mifflin-St Jeor equation uses a different constant for men and women that reflects average differences in body composition.

Are the figures accurate for me personally?

They are estimates based on population averages, and your actual needs may differ depending on your body composition and true activity level.

Methodology and review

The calculator applies the Mifflin-St Jeor equation to estimate BMR from weight, height, age and sex, then multiplies it by the chosen activity factor to give an approximate TDEE.

Results are estimates for informational purposes only and are not medical advice or diagnosis. Consult a professional before starting any diet or training programme.

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