Enter your age, weight, serum creatinine, and sex to estimate your creatinine clearance (CrCl) using the Cockcroft-Gault formula. The calculator returns your CrCl in mL/min, helping clinicians assess kidney function and guide drug dosing decisions.
Creatinine Clearance (CrCl)
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Kidney Function Stage
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Formula
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The Cockcroft-Gault (CG) formula was developed in 1973 using data from 249 men with creatinine clearance ranging from approximately 30 to 130 mL/min. It estimates creatinine clearance (CrCl) using a patient's age, weight, sex, and serum creatinine. The formula is: CrCl = [(140 − age) × weight] / (72 × SCr) × 0.85 (if female).
Despite being over 50 years old, the CG formula remains widely used for drug dosing calculations because most pharmacokinetic studies and drug labeling were developed using CrCl derived from the Cockcroft-Gault equation. It provides a quick bedside estimate without requiring body surface area adjustment.
The CG formula is no longer recommended for estimating GFR because it was not developed using standardized (IDMS-traceable) creatinine values. More accurate equations, such as the CKD-EPI Creatinine Equation (2009) or the MDRD Study equation, are preferred for estimating GFR in clinical practice.
Yes — the CG equation is still recommended for drug dosing decisions, particularly for renally cleared medications, since most drug regulatory approvals and dosing thresholds were established using CrCl estimates from this formula. Always consult clinical guidelines for specific drug dosing.
Creatinine clearance is expressed in milliliters per minute (mL/min). Normal values are generally 88–128 mL/min for adult females and 97–137 mL/min for adult males, though these ranges vary by age and body size.
Yes. The Cockcroft-Gault formula uses actual body weight in kilograms. In clinical settings, ideal body weight (IBW) or adjusted body weight (ABW) may be substituted for obese patients to avoid overestimating CrCl. This calculator uses the weight you enter directly.
Females typically have lower muscle mass than males, resulting in less creatinine production. The Cockcroft-Gault formula accounts for this by multiplying the result by 0.85 for female patients, yielding a lower CrCl estimate compared to males of the same age, weight, and serum creatinine.
A low CrCl suggests reduced kidney function. Values below 60 mL/min may indicate chronic kidney disease (CKD), and values below 15 mL/min may indicate kidney failure. Low CrCl requires adjustments in drug dosing to prevent toxicity from renally cleared medications.