Creatinine Clearance Calculator
Calculate estimated creatinine clearance (CrCl) using the Cockcroft-Gault equation. Enter age, sex, body weight, and serum creatinine. Supports mg/dL, µmol/L, kg, and lb.
Learn More About Creatinine Clearance
Want to understand the formula, calculation method, interpretation, limitations, and the difference between creatinine clearance and eGFR?
Enter Patient Values
Calculation Result
What Is Creatinine Clearance?
Creatinine clearance (CrCl) is an estimate of the volume of plasma from which creatinine is cleared by the kidneys per unit of time. It is commonly expressed in mL/min.
The traditional Cockcroft-Gault equation estimates creatinine clearance using age, body weight, sex, and serum creatinine concentration.
Creatinine clearance is different from estimated glomerular filtration rate (eGFR). The two calculations use different equations and are reported in different ways.
Cockcroft-Gault Creatinine Clearance Formula
For females, multiply the calculated result by 0.85.
The calculator automatically converts body weight from pounds to kilograms and serum creatinine from µmol/L to mg/dL before applying the conventional equation.
Creatinine Clearance Formula for Male
Creatinine Clearance Formula for Female
Creatinine Clearance Calculation Example
Consider a 45-year-old male with a body weight of 70 kg and serum creatinine of 1.2 mg/dL.
CrCl = 6650 ÷ 86.4
CrCl ≈ 77.0 mL/min
Creatinine Clearance in µmol/L
Laboratories outside the United States commonly report serum creatinine in µmol/L. To use the conventional Cockcroft-Gault equation, serum creatinine must be converted to mg/dL.
For example, a creatinine concentration of 106.08 µmol/L is approximately 1.20 mg/dL.
Creatinine Clearance in kg and lb
The Cockcroft-Gault equation requires body weight in kilograms. If body weight is reported in pounds, it can be converted using:
How to Use This Creatinine Clearance Calculator
- Enter the patient's age in years.
- Select male or female.
- Enter body weight.
- Select kg or lb.
- Enter serum creatinine.
- Select mg/dL or µmol/L.
- Click Calculate Creatinine Clearance.
- Review the estimated result in mL/min.
Creatinine Clearance Interpretation
Creatinine clearance is an estimate and should not be interpreted as an isolated diagnostic measurement. Age, body composition, clinical condition, serum creatinine, and the purpose of the calculation should all be considered.
| Estimated CrCl | General Context |
|---|---|
| ≥90 mL/min | Higher estimated clearance; interpretation depends on clinical context |
| 60–89 mL/min | Mildly reduced estimate |
| 30–59 mL/min | Moderately reduced estimate |
| 15–29 mL/min | Severely reduced estimate |
| <15 mL/min | Very severely reduced estimate |
These categories are provided for general educational context and should not be used alone to diagnose chronic kidney disease.
Creatinine Clearance vs eGFR
Creatinine clearance and eGFR are not interchangeable. They are calculated using different equations and may be used for different clinical purposes.
| Feature | Creatinine Clearance | eGFR |
|---|---|---|
| Common equation | Cockcroft-Gault | CKD-EPI and other validated equations |
| Body weight | Used | Generally not used |
| Common unit | mL/min | mL/min/1.73 m² |
| Body surface area normalized | No | Yes, for standard reporting |
Body Weight Selection in Cockcroft-Gault
Body weight is an important component of the Cockcroft-Gault equation. However, the appropriate weight can be more complicated in patients with obesity, underweight, edema, or unusual body composition.
Different clinical protocols may specify actual body weight, ideal body weight, or adjusted body weight. The appropriate method should therefore be determined according to the clinical purpose, drug-specific guidance, or institutional protocol.
Factors That Can Affect Creatinine Clearance
- Age and body weight.
- Serum creatinine concentration.
- Muscle mass and body composition.
- Changes in kidney function.
- Choice of body-weight parameter.
- Creatinine assay characteristics.
- Clinical conditions that alter creatinine production or elimination.
Limitations of the Cockcroft-Gault Equation
- It provides an estimate rather than a direct measurement of GFR.
- The calculated result is strongly influenced by the body weight used.
- Serum creatinine is influenced by muscle mass and other factors.
- The equation may be less reliable when kidney function is changing rapidly.
- Different kidney-function equations can produce different estimates.
- The original equation was developed from a specific study population and may not represent every modern patient population.
- Creatinine clearance may overestimate true GFR because creatinine is filtered and also undergoes tubular secretion.
Clinical Uses of Creatinine Clearance
Cockcroft-Gault estimated creatinine clearance has historically been important in clinical pharmacology and has been used in the dosing of selected medications.
The appropriate renal function equation should always be determined according to the medication, product labeling, institutional protocol, and current clinical guidance.
Frequently Asked Questions
What is creatinine clearance?
Creatinine clearance is an estimate of the volume of plasma cleared of creatinine per unit of time, commonly expressed in mL/min.
What formula does this calculator use?
This calculator uses the traditional Cockcroft-Gault equation to estimate creatinine clearance.
Can I enter creatinine in µmol/L?
Yes. Select µmol/L and the calculator converts the value to mg/dL before applying the Cockcroft-Gault equation.
Can I enter weight in pounds?
Yes. Select lb and the calculator automatically converts the weight to kilograms.
Is creatinine clearance the same as eGFR?
No. Creatinine clearance and eGFR are different estimates based on different equations and may have different clinical applications.
Why is 0.85 used for females?
The conventional Cockcroft-Gault equation applies a 0.85 factor to the calculated result for females.
Is Cockcroft-Gault used for drug dosing?
It has historically been used for dosing of many medications. However, the appropriate equation depends on the specific medication and current clinical guidance.
What does a low creatinine clearance mean?
A low calculated creatinine clearance may indicate reduced estimated renal function. It should be interpreted with clinical history, serum creatinine trends, and other relevant laboratory findings.
Complete Creatinine Clearance Guide
Learn more about the Cockcroft-Gault formula, calculation examples, creatinine clearance vs eGFR, body-weight considerations, and limitations.
Disclaimer
This calculator is provided for educational and laboratory reference purposes only. It does not replace professional medical evaluation, diagnosis, treatment, or medication-specific dosing guidance.
Do not use the calculated value as the sole basis for making clinical or medication decisions. Always consider current clinical guidelines, drug-specific recommendations, laboratory findings, and the complete clinical picture.
