Creatinine Clearance (Cockcroft-Gault)
CrCl (mL/min) = ((140 − age) × weight) / (72 × Scr) × 0.85 if female; Scr in mg/dL, weight in kg.
Calculator
How it works
What this tool does
It applies the 1976 Cockcroft-Gault equation widely used historically for medication dosing adjustments.
Formula
CrCl = ((140 − age) × weight_kg) / (72 × Scr_mg/dL); multiply by 0.85 for female patients.
References
Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.
Dosing & care
Teaching notes
- When weight exceeds ideal body weight, some references substitute adjusted or ideal weight in CG—this page uses actual weight only.
- Steady-state Scr and stable kidney function assumptions apply; acute changes invalidate the estimate.
Limitations
Inaccurate in extremes of age, amputation, pregnancy, rapidly changing renal function, and marked malnutrition or obesity; eGFR equations may be preferred for many modern drug labels.
Dosing context (teaching)
- Always match the renal dosing section of the specific drug monograph (CrCl vs eGFR vs TDM).
- Vancomycin, aminoglycosides, and chemotherapeutics often need TDM or pharmacist-guided dosing beyond a single estimate.
- Do not use this estimate as the sole basis for renally cleared drug changes in unstable patients.
Educational tool only—not for diagnosis or treatment decisions.