Making Metabolic Health
Free for Everyone
We're a small team of developers and health writers on a mission: give every person a clear picture of their metabolic health in under 60 seconds — no paywalls, no sign-ups.
Why We Built This
It started with a frustrating experience. One of our founders was trying to understand their metabolic age after seeing the term on a fitness app. Every resource they found was either locked behind a paywall, required an email sign-up, or used an outdated formula.
That seemed wrong. Metabolic health data is not a premium feature — it's fundamental wellness information. So we built a better tool.
We chose the Mifflin-St Jeor equation — the gold standard recommended by the Academy of Nutrition and Dietetics — ran all calculations client-side for complete privacy, and published it. No forms. No upsells. No friction.
Today, over 100,000 people use our calculator every month. We fund it through non-intrusive ads and plan to keep it free forever.
Our Values
Radically Accessible
Health data should never sit behind a login screen. Our calculator works instantly for anyone, anywhere — no account, no credit card, no catch.
Science-First, Always
Every formula and reference table on this site is sourced from peer-reviewed research. We cite our sources and update our content annually as evidence evolves.
Privacy by Design
Your age, weight, and height never leave your device. All calculations run in your browser. We don't even have a server to send your data to.
Honest & Transparent
We clearly state what our tool can and can't do. Metabolic age is a useful signal — not a diagnosis. We say that openly, every time.
From Input to Insight
You enter your stats
Age, gender, height, and weight — in metric or US units. No email, no account.
We calculate your BMR using Mifflin-St Jeor
The most accurate BMR formula for healthy adults (±5%), recommended by the Academy of Nutrition and Dietetics since 1990.
Your BMR is matched to age-group averages
We compare your BMR to population-level averages across six age bands (20s through 70+), separated by sex. The closest match is your metabolic age.
Results appear instantly — and stay private
Everything runs in JavaScript inside your browser. Nothing is transmitted. You get your metabolic age, BMR, and TDEE across six activity levels in real-time.
Meet the Founder
Usman
Founder Health ResearcherHi, I'm Usman — the person who designed, built, and writes for this site. I started Metabolic Age Calculator after seeing how many people had no idea what their metabolic age was, and every tool that could answer that question was buried behind paywalls or sign-up forms.
I have a deep interest in metabolic health, BMR science, and evidence-based fitness. My goal is simple: give you the most accurate, science-backed metabolic data in the shortest time possible — completely free, forever.
Ready to find out your metabolic age?
It takes 60 seconds. No email, no sign-up — just your result.
Try the Calculator Free → or get in touch with us