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.
Our Story
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 Every resource they found was either locked behind a paywall, required an email sign-up, or used an outdated formula.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.
What We Stand For
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.
How the Calculator Works
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.
Who We Are
We're BigTechies — a small, independent product studio focused on building useful, beautiful, and accessible health tools. We don't have venture-capital pressure to monetize your data. Our business model is simple: make great free tools, sustain them with ethical advertising.
Medical Disclaimer
This calculator is an educational tool, not a diagnostic device. Results are estimates based on population-level formulas. They are not medical advice and should not replace guidance from a qualified healthcare provider. Always consult a doctor or registered dietitian before making significant changes to your diet or exercise routine.
Ready to find out your metabolic age?
It takes 60 seconds. No email, no sign-up — just your result.