Practice and Tools
Creatinine Clearance Calculator (Cockcroft-Gault)
Estimate creatinine clearance (CrCl) in mL/min using the Cockcroft-Gault equation — the reference formula the FDA uses for most renal dose-adjustment labeling.
Enter values and press Calculate to see the result.
Enter the patient's age, weight, serum creatinine, and sex; the tool applies the 0.85 female multiplier automatically and flags severe renal impairment, elderly physiology, and unusually low SCr that can distort the estimate. Widely used for aminoglycoside, DOAC, vancomycin, and metformin dosing decisions at the bedside.
Method: Cockcroft-Gault
Inputs and units: Age (years); weight (kg or lb); serum creatinine (mg/dL); sex
Assumptions and limitations: Cockcroft-Gault estimates CrCl, not GFR. Do not use in acute kidney injury (SCr is unstable), pregnancy, amputees, or in patients with very reduced muscle mass — the estimate can be misleading.
Primary reference: Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.
Last reviewed: October 2026
Formula
CrCl (mL/min) = [(140 - age) x weight (kg)] / [72 x SCr (mg/dL)]
For female patients, multiply the result by 0.85.
Clinical Notes
- Most FDA drug labels still reference CrCl by C-G for dose thresholds; use the same method the label uses when adjusting a dose.
- In obesity, many clinicians substitute ideal or adjusted body weight rather than actual body weight; verify your institution's standard.
- This tool is for educational and clinical reference use. It is not a substitute for measured CrCl or clinical judgment.
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