eGFR Cockcroft-Gault Calculator
The Cockcroft-Gault equation estimates creatinine clearance in mL/min from age, body weight, sex and serum creatinine. Published in 1976, it remains the method many drug labels specify for renal dose adjustment. This calculator applies the published formula directly: it multiplies (140 minus age) by weight in kilograms, divides by (72 times serum creatinine), and applies the 0.85 factor for women. Enter your values to estimate creatinine clearance. This tool is for education and is not a substitute for clinical judgement.
Cockcroft-Gault formula
CrCl (mL/min) = ((140 - age) x weight in kg) / (72 x serum creatinine in mg/dL) For women: multiply the result by 0.85
The result is a raw creatinine clearance, not normalised to body surface area, and is the figure used by many drug dosing tables.
Worked example
A 60-year-old man weighing 80 kg with a creatinine of 1.0 mg/dL: CrCl = ((140 - 60) x 80) / (72 x 1.0) = 6,400 / 72 = 88.89 mL/min.
Cockcroft-Gault: frequently asked questions
What does the Cockcroft-Gault equation estimate?
The Cockcroft-Gault equation estimates creatinine clearance (CrCl) in millilitres per minute, which approximates kidney function. It was published in 1976 and remains widely used, especially for adjusting medication doses, because many drug labels base renal dosing on Cockcroft-Gault creatinine clearance rather than on the newer eGFR equations.
What is the Cockcroft-Gault formula?
Creatinine clearance equals (140 minus age in years) times body weight in kilograms, divided by (72 times serum creatinine in mg/dL). For women, the result is multiplied by 0.85 to account for lower average muscle mass. The inputs are age, weight, sex and serum creatinine.
How is this different from the CKD-EPI eGFR?
The CKD-EPI equation reports eGFR normalised to a body surface area of 1.73 square metres and is used to stage chronic kidney disease. Cockcroft-Gault gives a raw creatinine clearance in mL/min that depends on actual body weight and is the method many drug manufacturers specify for dose adjustment. The two can give different numbers for the same patient.
Which weight should I use?
The original equation uses actual body weight, which is the default here. In obese patients, clinicians sometimes use ideal or adjusted body weight to avoid overestimating clearance. Follow your clinical protocol or pharmacist guidance; this tool computes the equation with the weight you enter and is not a substitute for medical judgement.
Official sources
- National Kidney Foundation: GFR Calculator.
- National Institute of Diabetes and Digestive and Kidney Diseases: CKD Tests and Diagnosis.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.