Creatinine Clearance Calculator
Medical disclaimer: This Cockcroft-Gault estimate is for educational purposes only and is not a substitute for clinical testing or professional medical advice. Discuss any result with a qualified healthcare provider.
Creatinine clearance estimates how quickly the kidneys remove creatinine from the blood and is widely used to adjust medication doses. This calculator applies the Cockcroft-Gault equation, which combines age, body weight, sex, and serum creatinine rather than the race-free eGFR approach. Because it weighs absolute body mass, Cockcroft-Gault remains the reference many drug labels still cite for renal dosing. Results here are educational estimates and not a substitute for clinical laboratory testing.
Formula
CrCl = ((140 − age) × weight(kg) × sexFactor) / (72 × serumCreatinine)
- age
- Age in years
- weight
- Body weight in kilograms
- sexFactor
- 0.85 for female, 1.0 for male
- serumCreatinine
- Serum creatinine in mg/dL
How it works
- Enter your age, body weight (in kilograms or pounds), sex, and a serum creatinine value in mg/dL.
- The calculator multiplies (140 − age) by weight in kilograms, applies a 0.85 factor for females, and divides by 72 times the serum creatinine.
- The result is reported in mL/min along with a descriptive band from normal function down to kidney failure.
Worked example
A 60-year-old man weighing 80 kg with a serum creatinine of 1.0 mg/dL.
- Numerator = (140 − 60) × 80 × 1.0 = 6,400.
- Denominator = 72 × 1.0 = 72.
- CrCl = 6,400 ÷ 72 = 88.9 mL/min.
Estimated creatinine clearance of 88.9 mL/min (mild reduction band).
Frequently asked questions
- How is Cockcroft-Gault different from eGFR?
- Cockcroft-Gault uses absolute body weight, age, and sex to estimate clearance in mL/min, while modern eGFR equations like CKD-EPI 2021 normalize to body surface area and omit weight. Many drug-dosing guidelines still specify Cockcroft-Gault.
- Should I use actual, ideal, or adjusted body weight?
- This tool uses the weight you enter. Clinicians often substitute ideal or adjusted body weight in obese patients to avoid overestimating clearance, so a pharmacist may compute it differently for dosing.
- Can I rely on this result for medication decisions?
- No. This is an educational estimate, not medical advice. Serum creatinine varies with muscle mass, hydration, and lab method, so any dosing or clinical decision should be made by a qualified healthcare provider.