Biological Age Calculator

Calculate your biological age and metabolic age based on BMR, BMI, activity level, sleep, smoking and stress.

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Formulas

Mifflin-St Jeor

♂ BMR = 10W + 6.25H − 5A + 5
♀ BMR = 10W + 6.25H − 5A − 161
BMI = W / H²
W = kg, H = m, A = age

How to use?

  1. 1
    Enter Your Physical Details Enter age, gender, height and weight — BMR and BMI are calculated automatically.
  2. 2
    Answer the Lifestyle Questions Select your activity level, sleep quality, smoking status and stress level.
  3. 3
    See Your Biological Age Click Calculate — your biological age, metabolic age and BMR appear instantly.

FAQ

What is biological age?
Biological age estimates how old your body is physiologically. Unlike calendar age (based on your birth date), it reflects metabolic rate, BMI, activity level, sleep quality, smoking and stress. A healthy lifestyle can push biological age well below your calendar age.
What does metabolic age mean?
Metabolic age is calculated by comparing your BMR to the average BMR for your gender and body measurements across age groups. If your metabolic age is below your calendar age, your metabolism is running faster than average — usually a sign of more muscle mass and an active lifestyle.
Can I reduce my biological age?
Yes! Regular aerobic and resistance exercise, 7–9 hours of quality sleep, quitting smoking and managing stress can lower biological age by 5–15 years. Maintaining a healthy BMI is also critical.
How is BMR calculated?
This tool uses the Mifflin-St Jeor formula. For men: BMR = 10×Weight + 6.25×Height − 5×Age + 5. For women: BMR = 10×Weight + 6.25×Height − 5×Age − 161. BMR is the minimum calories needed for basic vital functions at complete rest.
Are these results a medical diagnosis?
No. This tool is for general information and motivation only; it does not replace medical diagnosis or health advice. If you have concerns about your health, consult a doctor.

What Is Biological Age?

Biological age is a holistic measure of how "old" your body is at the cellular, tissue and organ-system level. Unlike calendar age (your birthday), it varies based on lifestyle choices, genetics and environmental factors. Research shows that healthy habits can push biological age 10–15 years below calendar age.

Metabolic Age vs. Biological Age

Metabolic age is determined by comparing your BMR to age-group averages for the same gender. High muscle mass and an active lifestyle raise BMR, making you metabolically younger. Biological age is broader: it weighs BMI, exercise habits, sleep quality, smoking and stress together.

Factors That Affect Biological Age

  • Exercise: Regular resistance and aerobic training slows muscle loss and can reduce biological age by 4–8 years on average.
  • Sleep: 7–9 hours of quality sleep is critical for cell repair and cortisol balance.
  • Smoking: Long-term smoking shortens telomeres and can add 5–10 years to biological age.
  • Stress: Chronic stress accelerates inflammation and cellular aging via cortisol.
  • BMI: Staying in the normal range (18.5–24.9) minimises metabolic load on organs.

What Is BMR and Why Does It Matter?

Basal Metabolic Rate (BMR) is the calories you burn at complete rest for basic functions. This tool uses the Mifflin-St Jeor formula. BMR declines roughly 1–2% per decade with age, but this decline can be slowed by preserving muscle mass.

How to Lower Your Biological Age

At least 150 minutes of moderate aerobic exercise per week plus 2 resistance sessions is the standard recommendation. Quitting smoking improves telomere length and cardiovascular health visibly within 5 years. Mindfulness-based stress reduction also creates measurable improvements in biological age markers.

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