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ChronoAgePro

BMI, BMR & Healthy Body Weight Calculator

Calculate your Body Mass Index (BMI), WHO weight classification, Mifflin-St Jeor Basal Metabolic Rate (BMR), and Total Daily Energy Expenditure (TDEE) with support for Metric and Imperial units.

Body Mass Index & Metabolic Calculator

Health Screening Estimate

WHO classification, Basal Metabolic Rate (BMR), and TDEE calorie estimates.

cm
kg
Gender

Awaiting Biometric Data

Enter your height, weight, and age above to calculate your BMI and metabolic profile

The Science of Body Mass Index & Metabolic Rates

How BMI, BMR, and TDEE provide a comprehensive window into daily energy and physical health.

Mifflin-St Jeor BMR Equation

The Mifflin-St Jeor formula is widely considered by clinical dietitians to be the most reliable equation for calculating Basal Metabolic Rate without specialized calorimetry equipment:

  • Men: $\text{BMR} = 10 \times \text{weight(kg)} + 6.25 \times \text{height(cm)} - 5 \times \text{age} + 5$
  • Women: $\text{BMR} = 10 \times \text{weight(kg)} + 6.25 \times \text{height(cm)} - 5 \times \text{age} - 161$

Understanding BMI Prime & Ponderal Index

BMI Prime divides your BMI by the upper limit of normal weight ($25.0$). A BMI Prime below $1.0$ indicates you are within or below the upper threshold of healthy weight. The Ponderal Index scales weight against the cube of height ($\text{kg/m}^3$), making it useful for tall and short individuals.

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Frequently Asked Questions

Technical clarity, mathematical standards, and data privacy principles powering ChronoAge Pro.

Most online age calculators simply divide your total days by 365 or 365.25, which leads to rounding errors and ignores varying month lengths or calendar leap centuries (such as the 100/400-year rules). ChronoAge Pro calculates your exact chronological age down to the second using calendar-accurate date arithmetic, projects your age across 7 other planets using Keplerian orbital periods, and integrates biological metrics (heartbeats, breaths, WHO-standard BMI/BMR)—all 100% client-side without storing your data.
Absolutely. All calculations execute entirely inside your web browser (client-side execution). No personal birth dates, biometric inputs, or calculated results are ever collected, tracked, or transmitted to external servers. Once you refresh or close the page, your data is gone.
The platform synchronizes your input birth date and time with your device's internal system clock and local time zone offset. Using step-by-step calendar advancement, it accounts for exact leap seconds, month-length variations, and live ticker intervals in real time without lag.
A planetary year is defined by the time it takes a planet to complete one full orbit around the Sun. Because orbital periods vary drastically across the Solar System, ChronoAge Pro uses real Keplerian astronomical data to translate your Earth lifespan into equivalent planetary years and upcoming solar birthdays for Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune.
Biological metrics represent scientifically grounded baselines derived from healthy resting physiology—modeled around an average resting heart rate of ~80 beats per minute and ~16 breaths per minute. Daily calorie targets (BMR and TDEE) utilize the clinically validated Mifflin-St Jeor formula paired with World Health Organization (WHO) BMI classifications.
For individuals born on a leap day, the system incorporates Gregorian calendar rules to accurately project upcoming milestones and countdowns, properly defaulting to March 1 (or February 28, depending on regional standards) during non-leap years.