Clinical tool
Creatinine Clearance
Cockcroft-Gault creatinine clearance, used for many drug-dosing decisions.
Calculation details
CrCl = ((140 − age) × weight in kg) ÷ (72 × serum creatinine in mg/dL), multiplied by 0.85 for women.
Creatinine in µmol/L is converted first: mg/dL = µmol/L ÷ 88.4.
For staging chronic kidney disease use the eGFR calculator (CKD-EPI 2021). Cockcroft-Gault remains the reference for drug dosing when the drug reference specifically uses CrCl, because most renal dosing guidance was derived with it; the two are not interchangeable. Which weight to enter matters: use actual body weight normally, ideal body weight if obese, and adjusted body weight in significant obesity. The equation assumes stable renal function and is invalid in acute kidney injury, where creatinine lags behind real clearance. It also overestimates in muscle wasting, amputation and advanced age.
For practising medics only. Clinical tools support judgement, they do not replace it. Always verify results against current guidelines and the patient in front of you.