Creatinine Clearance Calculator

Creatinine Clearance Calculator – Understand Your Estimated Kidney Function

Creatinine clearance (CrCl) is an estimate of kidney function based on how efficiently your kidneys clear creatinine from the blood. It is often used to approximate glomerular filtration rate (GFR) and to help guide medication dosing in people with reduced kidney function.

This Creatinine Clearance Calculator lets you estimate CrCl in three ways: using the Cockcroft–Gault equation, a simplified 24-hour urine clearance method, and a body surface area (BSA)–standardized value. The results are for education only and must not replace professional medical advice, diagnosis, or treatment.

How the Creatinine Clearance Calculator Works

The calculator supports multiple methods commonly used in clinical practice and teaching:

• Cockcroft–Gault equation using age, weight, sex, and serum creatinine
• 24-hour urine creatinine clearance using urine creatinine, urine volume, serum creatinine, and collection time
• BSA-standardized CrCl to express creatinine clearance relative to a standard body surface area of 1.73 m²

Cockcroft–Gault Creatinine Clearance Formula

The Cockcroft–Gault equation is one of the classic methods to estimate creatinine clearance from a single blood test:

This equation assumes relatively stable kidney function and typical muscle mass for age and sex. The calculator automatically applies the 0.85 adjustment factor for females and displays the result in mL/min, along with a broad interpretation band based on the numeric value.

24-hour Urine Creatinine Clearance

If you have laboratory measurements from a timed urine collection, creatinine clearance can also be estimated using urine creatinine, urine volume, and serum creatinine:

This method can reflect actual creatinine excretion over the collection period, but it depends heavily on accurate timing and complete collection of all urine. The calculator uses a simplified version of this equation for educational use.

Standardized Creatinine Clearance (per 1.73 m²)

Because larger individuals naturally have higher kidney filtration due to greater body size, creatinine clearance values are sometimes standardized to a body surface area of 1.73 m², which is a typical adult reference BSA:

The BSA tab allows you to enter a creatinine clearance value and your body surface area to calculate a standardized clearance. This is useful for comparing kidney function across individuals with different body sizes or when aligning with lab-reported GFR values.

Typical Interpretation Bands (Educational Only)

The calculator provides a broad interpretation label based on the numerical creatinine clearance. These bands are simplified and should not be used as a substitute for clinical staging or decision-making:

• ≥ 90 mL/min: Typically within normal range for many adults
• 60–89 mL/min: Mildly reduced kidney function
• 30–59 mL/min: Moderately reduced
• 15–29 mL/min: Severely reduced
• < 15 mL/min: Very severe reduction

Actual clinical classification of chronic kidney disease (CKD) depends on many additional factors, including repeated measurements over time, albumin in the urine, imaging, and medical history.

When Creatinine Clearance Is Used

• Roughly estimating kidney function in outpatient and inpatient settings
• Supporting medication dosing decisions for drugs cleared by the kidneys
• Teaching and understanding how kidney filtration relates to creatinine levels
• Comparing different methods of kidney function estimation (CrCl vs. eGFR)

Limitations of Creatinine Clearance Estimation

Although creatinine clearance calculators are widely used, they have important limitations:

• Creatinine production varies with muscle mass, diet, and illness
• Equations may be inaccurate in people with very low or very high body weight
• Not reliable in acute kidney injury where creatinine is changing rapidly
• Different labs and guidelines may prefer other equations (for example, CKD-EPI for eGFR)

Because of these limitations, creatinine clearance values from this calculator should not be used alone to diagnose kidney disease or adjust medications.

How to Use This Creatinine Clearance Calculator

• Select the method tab: Cockcroft–Gault, 24-hour Urine, or BSA Standardized
• Enter the required values in the appropriate units
• Click the calculate button to see creatinine clearance and an interpretation band
• Use the values for education, self-study, or to better understand lab discussions with your healthcare provider

Important Safety Note

This Creatinine Clearance Calculator is provided for general information and educational purposes only. It does not provide medical advice, diagnosis, or treatment and must not be used to start, stop, or adjust any medication. Always discuss kidney function and treatment decisions with a qualified healthcare professional who can interpret your laboratory results in context.

Related Health Calculators from MyTimeCalculator

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• Body Surface Area (BSA) Calculator
• Blood Pressure Calculator