Basal Metabolic Rate is the number of calories your body needs to perform basic life-sustaining functions at complete rest.

Total Daily Energy Expenditure — your BMR multiplied by an activity factor, estimating total calories burned per day.

Why does the Mifflin-St Jeor equation use age, weight, height, and sex?

All four factors influence metabolic rate — metabolism naturally varies with body size, and typically declines somewhat with age, while also differing on average between sexes due to differences in typical body composition.

Which activity level should I choose?

Pick the option that best reflects your typical week, not just how you feel on your most active day — most people tend to overestimate their activity level, so err toward the more conservative option if you're unsure.

Should I eat exactly at my TDEE every day?

TDEE is a useful estimate for maintaining your current weight, but individual needs vary day to day — treat it as a starting reference point to adjust from based on your own goals and how your body responds over time.

Health & Fitness Cluster

BMR Calculator

Calculate your basal metabolic rate.

TL;DR: BMR Calculator is a free, browser-based tool that lets you calculate your basal metabolic rate.

Units

Gender

Age (years)

Weight (kg)

Height (cm)

Activity level

What Is the BMR Calculator?

The BMR Calculator computes health and physiological metrics based on established clinical formulas, helping you monitor fitness benchmarks, body composition, and daily nutritional requirements.

Step-by-Step: Using This Calculator

Select your measurement system (Metric or Imperial units).
Enter your height, weight, age, and relevant biometric measurements.
View your calculated biometric score and clinical classification category.
Use the target recommendations to guide sustainable fitness and wellness goals.

Mathematical Formula & Methodology

Here is the standard mathematical equation used to calculate this result accurately:

\text{Mifflin-St Jeor: } \text{BMR} = 10W + 6.25H - 5A + S

Formula Variables Explained:
Where W is weight in kg, H is height in cm, A is age in years, and S is gender constant (+5 for males, -161 for females).

Step-by-Step Worked Example

A 30-year-old male weighing 80 kg at 180 cm: $\text{BMR} = (10 \times 80) + (6.25 \times 180) - (5 \times 30) + 5 = 800 + 1125 - 150 + 5 = 1,780 \text{ kcal/day}$

Maximize Your Results

Track Long-Term Trends: Measure biometrics under consistent conditions (e.g., first thing in the morning) rather than stressing over daily fluctuations.
Holistic Context: Treat formula calculations as broad wellness guidelines rather than strict medical diagnoses.
Consult Professionals: Consult a physician or registered dietitian before making substantial dietary or caloric adjustments.

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100% Client-Side Privacy Guarantee

All processing runs locally inside your browser using JavaScript and HTML5 APIs. Your data, files, and inputs are never uploaded to any remote server. Complete privacy by design.

Frequently Asked Questions

: Basal Metabolic Rate is the number of calories your body needs to perform basic life-sustaining functions at complete rest.
: Total Daily Energy Expenditure — your BMR multiplied by an activity factor, estimating total calories burned per day.
: All four factors influence metabolic rate — metabolism naturally varies with body size, and typically declines somewhat with age, while also differing on average between sexes due to differences in typical body composition.
: Pick the option that best reflects your typical week, not just how you feel on your most active day — most people tend to overestimate their activity level, so err toward the more conservative option if you're unsure.
: TDEE is a useful estimate for maintaining your current weight, but individual needs vary day to day — treat it as a starting reference point to adjust from based on your own goals and how your body responds over time.

Cite This Tool

Referencing this tool in a paper, article, or bibliography? Copy a ready-made citation below.

NexLove.org. (2026). BMR Calculator [Software]. https://nexlove.org/tools/bmr-calculator.html

“BMR Calculator.” NexLove.org, 2026, nexlove.org/tools/bmr-calculator.html.

NexLove.org (2026) BMR Calculator. Available at: https://nexlove.org/tools/bmr-calculator.html (Accessed: 2026).

@misc{nexlove_bmr_calculator,
  title = {BMR Calculator},
  author = {{NexLove.org}},
  year = {2026},
  url = {https://nexlove.org/tools/bmr-calculator.html}
}

Embed This Tool

Add the live BMR Calculator tool to your own website with this snippet — it loads the real, working tool in an iframe, not a static screenshot.

<iframe src="https://nexlove.org/embed/bmr-calculator.html" width="100%" height="600" style="border:1px solid #e2e8f0;border-radius:12px" title="BMR Calculator — NexLove.org" loading="lazy"></iframe>

Understanding the BMR Calculator

This calculator provides instant, client-side computations designed for precision and ease of use.

Key Benefits

Instant Execution: No page reloads required. The math is calculated dynamically as you type.
Private & Secure: No financial, personal, or numerical data is transmitted. All calculations run in your browser's memory.

Disclaimer: While we strive for absolute accuracy, the BMR Calculator should be used for informational purposes. Always verify critical calculations with a licensed professional where applicable.

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