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Generated on: July 20, 2026 at 09:33 PM

Creatinine Clearance Calculator

Inputs

GenderMale
Age50 yr
Weight70 kg
Serum Creatinine88 µmol/L

Visualization

Creatinine Clearance (CrCl)
15mL/min
30mL/min
60mL/min
90mL/min
Kidney failure
Severely reduced
Moderately reduced
Mildly reduced
Normal

This is an estimate that becomes unreliable at the extremes of body weight, in unstable kidney function, and in pregnancy. Drug dosing and clinical decisions must be made by a qualified professional.

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Health

Creatinine Clearance Calculator

Estimate creatinine clearance with the Cockcroft-Gault formula from age, weight, sex, and serum creatinine — the historical reference for renal drug dosing.

Inputs

yr
18 – 110 yr
20 – 250 kg
18 – 1,326 µmol/L

Results

Enter a value to see results.

mL/min
Creatinine Clearance (CrCl)
15mL/min
30mL/min
60mL/min
90mL/min
Kidney failure
Severely reduced
Moderately reduced
Mildly reduced
Normal

For these inputs, the estimated creatinine clearance is ....

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Creatinine Clearance

Creatinine clearance is an estimate of how much blood plasma the kidneys clear of creatinine each minute, and it serves as a practical proxy for the glomerular filtration rate. This calculator uses the Cockcroft-Gault formula, which estimates clearance from age, weight, sex, and serum creatinine — entered in either conventional (mg/dL) or SI (µmol/L) units — without needing a timed urine collection.

Why it is still used

Although laboratories now report an estimated glomerular filtration rate from newer equations, Cockcroft-Gault remains the reference for adjusting drug doses in kidney impairment. Many medications had their renal dosing thresholds validated against this formula, so it continues to guide prescribing even where eGFR is used to stage chronic kidney disease.

The formula

With creatinine in µmol/L, age in years, and weight in kilograms:

CrCl=(140−age)×weight×kcreatinine\mathrm{CrCl} = \dfrac{(140 - \text{age}) \times \text{weight} \times k}{\text{creatinine}}

where the constant k is 1.23 for men and 1.04 for women. Clearance falls as age and creatinine rise and increases with body weight.

With creatinine in mg/dL, age in years, and weight in kilograms:

CrCl=(140−age)×weight72×creatinine×(0.85 if female)\mathrm{CrCl} = \dfrac{(140 - \text{age}) \times \text{weight}}{72 \times \text{creatinine}} \times (0.85 \text{ if female})

Clearance falls as age and creatinine rise and increases with body weight; the female result is scaled down by 15% for lower average muscle mass.

Worked example

For a 50-year-old man weighing 70 kg with a creatinine of 88 µmol/L:

CrCl=(140−50)×70×1.2388=774988=88 mL/min\begin{aligned} \mathrm{CrCl} &= \dfrac{(140 - 50) \times 70 \times 1.23}{88} \\ &= \dfrac{7749}{88} \\ &= 88 \text{ mL/min} \end{aligned}

For a 50-year-old man weighing 70 kg with a creatinine of 1.0 mg/dL:

CrCl=(140−50)×7072×1.0=630072=87.5 mL/min\begin{aligned} \mathrm{CrCl} &= \dfrac{(140 - 50) \times 70}{72 \times 1.0} \\ &= \dfrac{6300}{72} \\ &= 87.5 \text{ mL/min} \end{aligned}

A clearance near 88 mL/min is in the mildly-reduced-to-normal range.

Limitations

The estimate is unreliable at the extremes of body weight, in rapidly changing kidney function, and in pregnancy, and it depends on which weight is entered. It supports dosing decisions but does not replace clinical judgement. For a related body-size measure used in dosing see the Body Surface Area (BSA) Calculator.

Frequently Asked Questions (FAQ)

What is creatinine clearance?

Creatinine clearance is the volume of blood plasma cleared of creatinine per minute, expressed in mL/min. Because creatinine is produced at a fairly steady rate and removed mostly by the kidneys, its clearance approximates the glomerular filtration rate, the standard measure of kidney function. The Cockcroft-Gault formula estimates it from routine variables without a timed urine collection.

How does Cockcroft-Gault differ from eGFR?

Modern laboratories usually report an estimated glomerular filtration rate from equations such as CKD-EPI, normalised to a body surface area of 1.73 m². Cockcroft-Gault instead estimates an absolute clearance in mL/min that scales with actual body weight. Many drug-dosing references were validated against Cockcroft-Gault, so it remains the preferred estimate for renal dose adjustment even though eGFR is used for staging chronic kidney disease.

Which body weight should be entered?

For people near their ideal weight, actual body weight is appropriate. In obesity the formula can overestimate clearance, so many clinicians use ideal or an adjusted body weight instead. The choice affects the result substantially, which is why dosing decisions should follow a clinical protocol rather than the raw output.

Disclaimer

This is an estimate that becomes unreliable at the extremes of body weight, in unstable kidney function, and in pregnancy. Drug dosing and clinical decisions must be made by a qualified professional.

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