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.
Creatinine Clearance Calculator (Cockcroft-Gault)
Estimate creatinine clearance (CrCl) using the 1976 Cockcroft-Gault equation. Widely used for renal drug-dosing adjustments per FDA labeling. Supports mg/dL and umol/L, kg and lb, and applies IBW/AdjBW correction when BMI > 30.
About Cockcroft-Gault & Creatinine Clearance
The Cockcroft-Gault (C-G) equation was published in 1976 and estimates creatinine clearance from age, sex, weight, and serum creatinine. Despite being decades old, it remains the formula referenced on the majority of FDA drug labels for renal dose adjustment. When a label says "adjust for CrCl < 50 mL/min", it almost always means CrCl estimated by C-G, not eGFR by CKD-EPI. This makes C-G the standard for inpatient and outpatient drug dosing in the United States.
For diagnosing and staging chronic kidney disease (CKD), the 2021 CKD-EPI race-free equation is now preferred by KDIGO and most US guidelines because it directly estimates GFR (mL/min/1.73 m²) and is better validated across populations. CKD-EPI is what your lab usually reports as "eGFR". CrCl from C-G slightly overestimates true GFR because creatinine is also secreted by the renal tubules. Use CKD-EPI for staging and prognosis, and Cockcroft-Gault when a drug label specifically calls for CrCl.
Both equations assume steady-state serum creatinine. They are unreliable in acute kidney injury (rapidly changing creatinine), in patients with very low muscle mass (elderly, amputees, paraplegics, severe malnutrition) where creatinine is low and clearance is overestimated, and in extremes of body size. In obesity (BMI > 30), using total body weight in C-G overestimates clearance; most pharmacy practice uses IBW, or AdjBW when IBW would underestimate. For underweight patients, using actual weight is appropriate.
Educational tool only. Not for clinical decisions without verification by a licensed clinician. Drug dosing should follow current institutional pharmacy guidance and the specific FDA label for each medication.