Creatinine Clearance Calculator (Cockcroft-Gault)
Estimate creatinine clearance with the 1976 Cockcroft-Gault formula. Used on most FDA drug labels for renal dose adjustment. Supports mg/dL and umol/L, kg and lb, and IBW/AdjBW correction for obese patients.
HEALTHCockcroft-Gault creatinine clearance calculator for kidney function assessment and renal drug dosing. Enter age, sex, weight, serum creatinine, and optionally height to handle obesity correction. Returns CrCl in mL/min, the corresponding KDIGO CKD stage, and BMI-aware IBW/AdjBW alternatives.
The Cockcroft-Gault equation (1976) is: CrCl_male (mL/min) = ((140 − age) × weight_kg) / (72 × Scr_mg/dL); for females, multiply by 0.85. To convert serum creatinine from umol/L to mg/dL, divide by 88.4. Devine ideal body weight (IBW) is 50 + 2.3 × (inches over 60) for males and 45.5 + 2.3 × (inches over 60) for females. When BMI > 30, pharmacy practice generally substitutes IBW, or Adjusted Body Weight (AdjBW = IBW + 0.4 × (TBW − IBW)) to avoid overestimating clearance from total body weight. Worked example: 65-year-old male, 70 kg, Scr 1.0 mg/dL → CrCl = ((140 − 65) × 70) / (72 × 1.0) = (75 × 70) / 72 = 72.9 mL/min, a mild reduction (G2). The same patient with Scr 1.5 mg/dL would have CrCl ≈ 48.6 mL/min (G3a), and many drugs (vancomycin, DOACs, gabapentin, metformin) need dose adjustment below 50-60 mL/min. CrCl by Cockcroft-Gault is the standard input for FDA-label renal dosing; CKD-EPI 2021 eGFR is preferred for CKD staging and prognosis.