Creatinine Clearance Calculator
Estimate your creatinine clearance using the Cockcroft-Gault equation.
What is creatinine clearance?
Creatinine clearance is an estimate of how much blood your kidneys clear of creatinine each minute. Creatinine is a waste product made by your muscles at a fairly steady rate, so how quickly the kidneys remove it is a useful index of kidney filtration. This calculator uses the Cockcroft-Gault equation, which predicts clearance from your age, weight, sex and serum creatinine.
How this calculator works
It applies the formula CrCl = ((140 - age) x weight x 0.85-if-female) / (72 x serum creatinine), with weight in kg and creatinine in mg/dL. Use the toggles if your weight is in pounds or your creatinine is reported in micromoles per litre. Everything is calculated in your browser and nothing is stored.
Creatinine clearance vs eGFR
These two numbers answer similar questions in different ways:
- eGFR (the 2021 CKD-EPI equation) is the modern standard for staging chronic kidney disease. It is normalised to a standard body size (1.73 m2).
- Creatinine clearance (Cockcroft-Gault) uses your actual weight and is not normalised. It remains widely used in hospitals to work out safe doses of medicines that the kidneys clear.
For staging kidney disease, prefer eGFR. For drug dosing, your doctor or pharmacist may specifically want the Cockcroft-Gault value.
What your result means
Roughly, 90 mL/min or above is normal, 60 to 89 is mildly reduced, 30 to 59 is moderately reduced, and below 30 is severely reduced. Clearance naturally declines with age and lower muscle mass, so a number a little below 90 is not automatically a problem. Always interpret it together with your eGFR, urine tests and clinical picture with your doctor.
Frequently asked questions
What is creatinine clearance?
It estimates how quickly your kidneys clear creatinine from the blood, which is a marker of how well they filter. The Cockcroft-Gault equation predicts it from your age, weight, sex and serum creatinine.
How is this different from eGFR?
eGFR (the 2021 CKD-EPI equation) is the modern standard for staging chronic kidney disease and is normalised to body size. Creatinine clearance from Cockcroft-Gault uses your actual weight and is still widely used to dose medications.
Which weight should I enter?
The classic input is your actual body weight. In significant obesity an adjusted weight is sometimes used instead, so check with your doctor or pharmacist for drug-dosing decisions.
Why does it ask for sex?
Women on average have lower muscle mass, which produces less creatinine, so the equation multiplies the result by 0.85 for females.
Is a value below 90 abnormal?
Not necessarily. Clearance falls gradually with age and lower muscle mass. Interpret it alongside your eGFR, urine tests and overall health with your doctor.
Formula source: Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31-41.
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