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BMR Calculator.

Calculate your Basal Metabolic Rate (BMR) using Mifflin-St Jeor, Revised Harris-Benedict, and Katch-McArdle formulas.

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Unit System
Gender

Required for Katch-McArdle formula to determine lean body mass.

Your Basal Metabolic Rate (BMR)

1674kcal/day

This is the number of calories your body needs to survive at absolute rest, without any activity or digestion.

Compare BMR Formulas

Mifflin-St Jeor

1674 kcal

Revised Harris-Benedict

1724 kcal

Katch-McArdle

N/A

Daily Calorie Intake by Activity Level (TDEE)

Activity LevelCalories
SedentaryLittle or no exercise2009 kcal
Lightly ActiveLight exercise 1-3 days/week2302 kcal
Moderately ActiveModerate exercise 3-5 days/week2595 kcal
Very ActiveHard exercise 6-7 days/week2888 kcal
Extremely ActiveHard daily exercise & physical job3181 kcal

FAQs

What is Basal Metabolic Rate (BMR)?

BMR is the minimum number of calories your body needs to maintain basic life-sustaining functions (like breathing and circulation) at complete rest.

Which BMR formula is the most accurate?

The Mifflin-St Jeor equation is widely considered the most accurate for modern lifestyles. If you know your body fat percentage, the Katch-McArdle formula is highly recommended as it accounts for lean muscle mass.

What is the difference between BMR and RMR?

BMR (Basal Metabolic Rate) is measured under strict laboratory conditions at rest. RMR (Resting Metabolic Rate) is measured under less restrictive conditions and is slightly higher but close enough for daily planning.

How does BMR help with weight loss?

Your BMR is the foundation of your daily calorie expenditure. By adding your activity level, you get your Total Daily Energy Expenditure (TDEE). Eating below your TDEE creates a calorie deficit for weight loss.

Cite this calculator

Canonical URL: https://mathify.one/es/fitness/bmr

Cite as: Mathify. (2026). Calculadora de TMB. https://mathify.one/es/fitness/bmr

Use Cases

Weight Management Planning

Determine your resting calorie burn to set realistic calorie targets for weight loss, gain, or maintenance.

Example: If your BMR is 1,500 calories, you might aim for 1,200–1,300 calories daily to lose weight.

Nutrition and Fitness Tracking

Use BMR as a baseline to calculate total daily energy expenditure (TDEE) and adjust macronutrient intake.

Example: Combine BMR with activity level to estimate daily calorie needs for training.

Frequently Asked Questions

What is BMR and why is it important?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain vital functions like breathing and circulation. It forms the baseline for daily calorie needs, helping you manage weight or plan nutrition.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is widely considered the most accurate for the general population. The Revised Harris-Benedict is also reliable, while Katch-McArdle is best for lean individuals if you know your body fat percentage.
How does body fat percentage affect BMR?
Muscle tissue burns more calories than fat, so a lower body fat percentage (more muscle) typically increases BMR. The Katch-McArdle formula uses body fat to estimate lean mass, making it more precise for athletic or muscular individuals.

Tips & Common Mistakes

Tips

  • Enter your height in either centimeters or feet/inches – the calculator will handle the conversion.
  • For the Katch-McArdle formula, provide an accurate body fat percentage for the best estimate.
  • Use the same formula consistently when tracking changes over time to see trends.
  • BMR is a resting estimate; multiply by an activity factor to estimate total daily burn.

Common Mistakes to Avoid

  • Using the wrong height unit – double-check if you entered cm or ft/in.
  • Forgetting to enter body fat percentage when using Katch-McArdle, which then may not be accurate.
  • Assuming BMR equals total daily calorie needs – it's only the resting portion.

Last updated: August 13, 2026