Creatinine Clearance Calculator (Cockcroft-Gault)
Estimate creatinine clearance (CrCl) — a proxy for glomerular filtration rate — using the Cockcroft-Gault equation. Enter age, sex, weight, and serum creatinine from a blood test to get CrCl in mL/min and the corresponding CKD stage.
let
Biological sex
kg
mg/dL
Estimated glomerular filtration rate (Cockcroft-Gault, 1976)
- 1
Age factor
140 − 45 = 95 - 2
Numerator
95 × 75 × 1 = 7125 - 3
Denominator
72 × 1 = 72 - 4
Creatinine clearance
7125 ÷ 72 = 99Cockcroft-Gault equation (1976).
Kako deluje ta kalkulator?
CrCl (mL/min) = [(140 − age) × weight_kg × 0.85ᶠ] ÷ (72 × serum creatinine_mg/dL). Values ≥ 90 are normal; 60–89 mildly reduced; 30–59 moderately reduced; 15–29 severely reduced; < 15 is kidney failure (KDIGO G5). Use lean body weight in obese patients. Consult a clinician for diagnosis and drug dosing.
Formula
How this is calculated
The Cockcroft-Gault equation, published in 1976, estimates creatinine clearance (CrCl) as a surrogate for glomerular filtration rate (GFR) — the volume of blood filtered by the kidneys per minute. Creatinine is a muscle waste product cleared almost entirely by the kidneys; when filtration declines, serum creatinine rises. The formula multiplies (140 − age) by body weight in kilograms and applies a sex correction factor of 0.85 for females (reflecting lower average muscle mass), then divides by 72 times the serum creatinine in mg/dL. The result is in mL/min.
CrCl from Cockcroft-Gault is not the same as the eGFR reported by modern laboratories, which typically uses the CKD-EPI 2021 equation and reports in mL/min/1.73 m². However, both are used to classify CKD severity: KDIGO 2012 defines G1 (≥ 90, normal), G2 (60–89, mildly decreased), G3a (45–59), G3b (30–44), G4 (15–29, severely decreased), and G5 (< 15, kidney failure). Cockcroft-Gault remains the preferred formula for drug dosing calculations in pharmacokinetics guidelines.
Limitations: the equation can overestimate CrCl in obese patients (use lean or ideal body weight), underestimate it in malnourished or very elderly patients with low muscle mass, and is unreliable with rapidly changing creatinine. Equations for children differ. Results are estimates for educational and general reference — clinical decisions require laboratory eGFR and specialist review.
Pogosta vprašanja
Normal CrCl is approximately 90–120 mL/min for healthy adults, declining with age. Values below 60 mL/min for three or more months indicate chronic kidney disease (CKD).
On average, women have less skeletal muscle mass than men and therefore produce less creatinine per kilogram of body weight. The factor 0.85 adjusts for this difference; without it CrCl would be overestimated in women.
In obesity, actual body weight overestimates CrCl because excess adipose tissue does not generate creatinine proportionally. Most pharmacokinetics guidelines recommend using lean or ideal body weight (IBW) for Cockcroft-Gault in patients whose actual weight exceeds IBW by more than 30%.
Znano tudi kot
TG we-Calculate Editorial Team. (2026). Creatinine Clearance Calculator (Cockcroft-Gault) [Online calculator]. TG we-Calculate. https://we-calculate.com/sl/calculator/crc-calculator
TG we-Calculate Editorial Team. "Creatinine Clearance Calculator (Cockcroft-Gault)." TG we-Calculate. 2026. https://we-calculate.com/sl/calculator/crc-calculator.
TG we-Calculate Editorial Team, "Creatinine Clearance Calculator (Cockcroft-Gault)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/sl/calculator/crc-calculator
@misc{wecalculate_crc_calculator, title = {Creatinine Clearance Calculator (Cockcroft-Gault)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/sl/calculator/crc-calculator}}, year = {2026}, note = {TG we-Calculate} }
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