The Cockcroft-Gault Equation Explained
Where the equation came from, what each term is doing, why the 0.85 female factor exists, and the assumptions that decide whether the number you get is usable.
6 min readCrCl Calculator
Renal function & drug dosing guides
The reasoning behind the calculators — why the equations work, where they fail, and how to avoid the errors that produce a confident wrong number.
All guides
Every article on this site
CrCl vs eGFR: What's the Difference?
Two numbers, different units, different purposes — and a conversion that is routinely done wrong. How creatinine clearance and estimated GFR actually relate.
6 min readeGFR / GFR Calculator
How to Adjust CrCl for Obese Patients
Ideal body weight, adjusted body weight, Salazar-Corcoran — which to use, when, and how much difference the choice actually makes to a dose.
6 min readSpecial Populations Calculator
Creatinine Clearance in Elderly Patients
Why a normal serum creatinine in an 84-year-old can hide severely reduced clearance, and whether rounding low creatinine values up to 1.0 is defensible.
5 min readSpecial Populations Calculator
24-Hour Urine Creatinine Clearance Test
How the test works, how to check whether the collection was actually complete, and why an incomplete collection is worse than no test at all.
6 min read24-Hour Urine CrCl Calculator
Renal Drug Dosing and Why CrCl Matters
How renal impairment changes drug handling, why dose reduction and interval extension are different tools, and where the common thresholds come from.
6 min readCrCl Calculator
CrCl in Amputees, Children & Race
Three populations where the standard approach is wrong: correcting weight after amputation, why Cockcroft-Gault must not be used in children, and why race went.
6 min readSpecial Populations Calculator
Understanding Serum Creatinine
Where creatinine comes from, why the reference range misleads, and the drugs, diets and assay quirks that move the number without touching the kidneys.
5 min readCrCl Calculator
10 Creatinine Clearance Mistakes
The errors that produce a confident wrong number — wrong weight basis, wrong units, wrong steady state, wrong measure entirely — and how to catch each one.
5 min readCrCl Calculator
GFR vs CrCl for Drug Dosing
Why drug labels still specify creatinine clearance when laboratories report eGFR, where the two diverge most, and how to decide when they disagree.
5 min readeGFR / GFR Calculator
More calculators
Calculators referenced in these guides
CrCl Calculator (Cockcroft-Gault)
Standard adult creatinine clearance with actual, ideal and adjusted body weight side by side.
Open calculatorCKD-EPI eGFR & CrCl Conversion Calculator
CKD-EPI 2021 creatinine, cystatin C and combined equations, plus Schwartz for children and a CrCl comparison.
Open calculatorCrCl for Obese, Elderly, Amputee & Pediatric Patients
Weight-basis selection, Salazar-Corcoran, amputation correction, paediatric equations and mL/hour output.
Open calculator24-Hour Urine Creatinine Clearance Calculator
Measured clearance from a timed collection, with a collection-adequacy check and BSA normalisation.
Open calculator
Put it into practice
Every guide here links back to the calculator it explains. Start with the standard Cockcroft-Gault tool.
Medical disclaimer: This calculator is intended for healthcare professional reference and educational purposes only. It does not replace clinical judgment or the advice of a licensed provider. Always verify dosing decisions against institutional protocol and current prescribing information.