Creatinine Clearance calculator
The creatinine clearance calculator estimates renal function in mL/min using the Cockcroft-Gault equation, from age, body weight, serum creatinine and sex. Estimated clearance is the value many drug references use to set renal dose adjustments, so it is the number nurses most often need at the bedside.
The equation
CrCl (mL/min) = (140 - age) x weight (kg) / (72 x serum creatinine in mg/dL), multiplied by 0.85 for female patients. Cockcroft and Gault published it in 1976 and it remains the basis of many renal dosing tables.
A worked example
A 70-year-old woman weighing 60 kg with a serum creatinine of 1.2 mg/dL: (140 - 70) x 60 / (72 x 1.2) = 48.6, times 0.85 = 41.3 mL/min.
Known caveats
It is an estimate, and it is least reliable in exactly the patients who matter most: obesity, very low muscle mass, amputation, pregnancy, and unstable or rapidly changing kidney function, where a single creatinine does not reflect a steady state.
Institutions differ on which body weight to use, and many now prefer a reported eGFR from the laboratory. Follow your local guidance rather than assuming this value is the one your pharmacy uses.
What this does not do
This does not adjust any drug dose, does not choose a weight convention for you, and does not distinguish estimated clearance from a measured or laboratory-reported eGFR. It gives no result in units other than mg/dL for creatinine. Every result is a check on your arithmetic, not a clinical decision. Confirm the order, the concentration on the label and your own policy before administering anything.
Frequently asked questions
Which weight should I use?
Institutions differ — actual, ideal or adjusted body weight are all in use, and the choice matters at the extremes. Follow your pharmacy or policy.
Is creatinine clearance the same as eGFR?
No. Cockcroft-Gault estimates creatinine clearance; laboratory eGFR uses different equations, often normalised to body surface area. Many renal dosing tables are still written against Cockcroft-Gault.
My laboratory reports creatinine in micromoles per litre.
This calculator expects mg/dL. Convert before entering: divide the micromoles per litre value by 88.4.
Can I use it in acute kidney injury?
With caution. The equation assumes a steady state, so a creatinine that is still rising or falling will mislead.
By The Nursana team · Last updated · Canonical: https://nursana.aoneahsan.com/tools/creatinine-clearance
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