Why
There are plenty of calculators on the web, but most of them:
- Demand an email address before showing a number
- Run their calculations on a server (so your weight, blood pressure, and cholesterol go to that server)
- Hide which formula they're actually using
- Surround the result with ads and upsells
This site does none of that. The math runs in your browser, the values you enter stay in your browser, every formula cites the paper it came from, and if you don't want to keep your data on this device you can clear it from any calculator page.
What's here
- Body composition:BMI, BMR, TDEE, body fat %, waist-to-hip, ideal body weight, body surface area
- Cardiovascular:MAP, pulse pressure, LDL estimate, cholesterol ratio, Framingham 10-year risk, CHA₂DS₂-VASc
- Metabolic:HOMA-IR, TyG, HbA1c → eAG, eGFR (CKD-EPI 2021), Cockcroft-Gault, FIB-4
- Neurological:GAD-7, Epworth Sleepiness Scale, STOP-BANG
- Fitness:Max heart rate (Tanaka), Karvonen zones, 1-RM (Epley), VO₂max (Cooper)
Each calculator's source line links to the original paper on PubMed, NEJM, WHO, or the NCBI Bookshelf.
How it works
- Single static site, no backend.
- Calculator math is plain JavaScript loaded by your browser.
- Values you enter in one calculator are remembered and pre-fill the matching fields in other calculators, stored only in
localStorageon your device. - Toggle metric / imperial and SI / US lab units from the header; conversions happen on the fly.
Methodology
Every formula on this site comes from a peer-reviewed publication or an authoritative guideline body, and the source link appears on each calculator page. Formula families include body composition estimates (Mifflin–St Jeor, Mosteller, Devine, US Navy, WHO); cardiovascular risk scoring (Framingham 2008 general CVD score, Friedewald LDL, WHO waist-hip thresholds); metabolic markers (HOMA-IR, CKD-EPI 2021, Cockcroft-Gault, FIB-4, ADAG HbA1c, TyG); validated clinical questionnaires (GAD-7, Epworth Sleepiness Scale, STOP-BANG); and fitness science (Tanaka MHR, Karvonen HRR, Epley 1RM, Cooper VO₂max).
Every output band (e.g. "Healthy weight" for BMI 18.5–24.9) reflects the cut-points from the cited paper or guideline body. Where the literature disagrees, the most widely-cited threshold is used and any relevant caveats are noted in the calculator card.
Review process
All formulas and reference ranges were reviewed against the source publications in June 2025 and will be updated whenever guideline bodies issue new recommendations. Each calculator page includes the original source citation with a direct link to the publication on PubMed, NEJM, WHO, or the NCBI Bookshelf, so users can verify the underlying evidence themselves.
Author
The Body Calculator was built by an independent developer with a software engineering background and an interest in evidence-based health literacy. Every formula comes from a peer-reviewed publication or guideline body, with the link shown on each calculator page. This site does not provide medical advice.
Not medical advice
See the Terms: every number here is for learning, not diagnosing. Talk to a qualified medical professional before acting on anything you see here.