Creator of MayoCalc · Cook Media Systems
I built MayoCalc because I kept running into the same problem: I'd search for a calculator online and land on a page buried in ads, gated behind an email signup, or running on formulas I couldn't verify. So I started building my own.
My background is in radiology and clinical imaging. That's where the health side of MayoCalc comes from. The CT Calcium Score Calculator uses exact per-year percentile lookup tables from the MESA study, not rough approximations. The MESA Risk Calculator implements the full 12-variable McClelland equation. The eGFR Calculator uses CKD-EPI 2021, not the older MDRD formula. When I say "research-backed," I mean I've read the papers and implemented the actual equations.
The finance side grew out of personal interest. I've spent years working through the math of retirement planning, tax optimization, and investment returns. The Advanced FIRE Calculator runs historical backtests against every rolling period in Robert Shiller's dataset from 1871 to present. The state paycheck calculators use 2026 federal and state brackets verified against IRS and state revenue department data.
Everything on MayoCalc runs client-side in your browser. No data leaves your device. No accounts, no email gates, no paywalls. The tools are free because I believe everyone deserves access to good math.
Health content references the ADA, AHA, ACC, CDC, NIH, WHO, and KDIGO guidelines. Clinical calculators use peer-reviewed equations (Mifflin-St Jeor, CKD-EPI 2021, Navy body fat method, MESA CHD risk model). Every source is linked so you can verify independently.
Financial content draws from the Federal Reserve Survey of Consumer Finances, IRS publications, Fidelity, Vanguard, and Bureau of Labor Statistics data. Tax brackets and contribution limits are updated annually and verified against IRS announcements.
If you find an error, please tell me. Accuracy corrections are the highest priority in my inbox: [email protected].