Home / Clinical Calculator Formulas Reference (2026)

Clinical Calculator Formulas Reference (2026)

Every named clinical equation behind the MedCalcTools calculators, in one dated, sourced table you can cite or download.

Which formulas does MedCalcTools use?

MedCalcTools runs eight clinical reference calculators, and each one is built on a single named, published equation rather than an in-house guess: the Quetelet index for BMI (1832), the ADAG study equation for A1C to eAG (Nathan et al., 2008), the Cockcroft-Gault equation for creatinine clearance (1976), the 2021 CKD-EPI equation for eGFR, the Payne formula for albumin-corrected calcium (1973), the Mosteller formula for body surface area (1987), the Friedewald equation for LDL cholesterol (1972), and the Katz (1973) and Hillier (1999) factors for glucose-corrected sodium. The table below lists the author, year, and journal for each, with a downloadable CSV.

01 - Summary table
CalculatorFormula nameAuthor(s)YearJournal / source
BMI CalculatorQuetelet Index (Body Mass Index)Adolphe Quetelet; adult categories per CDC1832 / currentCDC
A1C to eAG CalculatorADAG study linear equationNathan DM, et al. (ADAG Study Group)2008Diabetes Care
Creatinine Clearance CalculatorCockcroft-Gault equationCockcroft DW, Gault MH1976Nephron
GFR Calculator2021 CKD-EPI creatinine equationInker LA, Eneanya ND, Coresh J, et al.2021New England Journal of Medicine
Corrected Calcium CalculatorPayne albumin correctionPayne RB, Little AJ, Williams RB, Milner JR1973British Medical Journal
Body Surface Area CalculatorMosteller formulaMosteller RD1987New England Journal of Medicine
LDL Cholesterol CalculatorFriedewald equationFriedewald WT, Levy RI, Fredrickson DS1972Clinical Chemistry
Sodium Correction CalculatorKatz formula / Hillier correction factorKatz MA; Hillier TA, Abbott RD, Barrett EJ1973 / 1999NEJM / American Journal of Medicine

Download the full table as CSV (includes the exact formula as implemented on each calculator page).

02 - Methodology

Where these numbers come from

Each row names the original paper or standards body that published the equation, not a secondary summary. We read the primary source (or, where the original journal article is paywalled, a citation-matched excerpt such as the PubMed abstract) before listing it here. The formula column mirrors the exact equation coded into that calculator's page, so you can check the math against the source yourself. No figure on this page is estimated, extrapolated, or generated; every cell is either a formula constant already published in the cited paper or the paper's own citation metadata (author, year, journal).

When this page is updated

This table is reviewed whenever a cited society revises a formula, such as the National Kidney Foundation's 2021 move to the race-free CKD-EPI equation. The date above reflects the last full review. If a professional body revises one of these equations, we will update the row, the CSV, and this date together.

Cite this page.
MedCalcTools. "Clinical Calculator Formulas Reference (2026)." Encore Editorial, 2026. https://medcalctools.com/clinical-calculator-formulas-reference-2026

Limits of this reference

This page is a citation index, not medical guidance. It documents which published equation each calculator uses and where that equation came from. It does not tell you which formula applies to your situation, does not recommend a dose, and is not a substitute for a licensed clinician who knows your history.

Medical disclaimer. This page is for educational purposes only, documents published clinical equations, and is not a substitute for professional medical advice. Consult a qualified healthcare provider.