Free tools

Health Calculators

Calculators built from published formulas and reference data. Every page names its sources, explains its limits and shows how we test it.

eGFR Calculator

Kidney function from creatinine and cystatin C, using the race-free CKD-EPI 2021 equations.

FIB-4 Liver Fibrosis Calculator

Liver scarring risk from age, AST, ALT and platelets, with the published cutoffs and age rules.

Insulin Resistance Calculator

HOMA-IR and the triglyceride-glucose (TyG) index from fasting labs.

Life's Essential 8 Calculator

The American Heart Association's 0-100 heart health score from eight measures.

VO2 Max Percentile Calculator

Where your VO2 max ranks for your age and sex, against measured treadmill data.

Functional Fitness Norms

Grip strength, chair stand and walking speed compared with published norms and cut-offs.

Lab Unit Converter

Convert results between mg/dL, mmol/L and other units, including HbA1c % and mmol/mol.

How we build these calculators

Each calculator uses the formula or reference table exactly as published, checked against the original paper or official source when the site is built. An automated test compares our code with an independent implementation, and where a paper gives worked examples, the calculator must reproduce them. When a source does not state a cutoff, we leave it out rather than guess.

These calculators are for education. They do not diagnose conditions or replace advice from your clinician.