Creatinine Clearance Calculator (Cockcroft–Gault)
Estimate creatinine clearance with the Cockcroft–Gault formula from age, weight, sex and serum creatinine. Widely used for drug-dose adjustment, it gives a result in mL/min. Enter your values below.
The Cockcroft–Gault formula
CrCl = [(140 − age) × weight(kg) × (0.85 if female)] ÷ (72 × Scr in mg/dL). The 0.85 factor accounts for lower average muscle mass; creatinine in µmol/L is divided by 88.4 to convert to mg/dL. Source: Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976.
Frequently asked questions
What is the Cockcroft–Gault formula?
The Cockcroft–Gault formula is CrCl (mL/min) = [(140 − age) × weight in kg × (0.85 if female)] ÷ (72 × serum creatinine in mg/dL). For example, a 60-year-old man weighing 80 kg with a creatinine of 1.2 mg/dL has a creatinine clearance of about 74 mL/min. A creatinine reported in µmol/L is divided by 88.4 first, and the 0.85 factor for women allows for lower average muscle mass. The output is an absolute clearance in mL/min, not a value indexed to body surface area.
What is a normal creatinine clearance?
In healthy adults, creatinine clearance is roughly 90–140 mL/min in men and 80–125 mL/min in women, falling with age. Because Cockcroft–Gault estimates clearance in mL/min (not indexed to body surface area), it is the value many drug labels specify for dose adjustment. This calculator bands the result as normal at 90 mL/min or above, mildly reduced from 60, moderately reduced from 30, severely reduced from 15, and in the kidney-failure range below that. Those bands echo the CKD stages but are applied to an un-indexed clearance, so treat them as orientation rather than formal staging.
How does creatinine clearance differ from eGFR?
Creatinine clearance from Cockcroft–Gault is reported in mL/min and uses actual body weight, while eGFR from CKD-EPI is standardised to 1.73 m² of body surface area. Many medication dosing recommendations were validated against Cockcroft–Gault, so it is still preferred for that purpose even though eGFR is now standard for staging kidney disease. Because it scales with actual body weight, Cockcroft–Gault tends to read higher than a CKD-EPI eGFR in heavier patients and lower in very light ones. The two answer different questions, so a difference between them is expected rather than an error.
Which body weight should I use?
Cockcroft–Gault was derived using actual body weight. In people who are markedly overweight or underweight, or who have significant fluid retention, the estimate can be misleading and clinicians may use an adjusted or ideal body weight instead. When in doubt, follow local pharmacy guidance.
Is this calculator free and private?
This creatinine clearance calculator is free and runs entirely in your browser. Nothing is uploaded or stored, and there is no sign-up. It is a reference tool for unit-level estimation, not a substitute for clinical judgement.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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