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Estimated kidney function is often discussed using creatinine clearance, calculated from a simple blood test result plus age, weight, and sex — this calculator is for educational purposes only and must not be used in place of a doctor's evaluation.
This calculator applies the widely-used Cockcroft-Gault formula to estimate creatinine clearance from your lab values.
How it works
Enter your age, weight, sex, and serum creatinine level (from a blood test, in mg/dL). The calculator applies the Cockcroft-Gault formula, which uses a lower multiplier for women to reflect typical differences in muscle mass, to estimate creatinine clearance in mL/min.
- Enter age.
- Enter weight (kg).
- Enter sex.
- Enter serum creatinine (mg/dL).
- Click Calculate to see your results.
Examples
45-year-old male, 80 kg
A 45-year-old man weighing 80 kg with a serum creatinine of 1.0 mg/dL has an estimated creatinine clearance of about 105.6 mL/min, within the normal range.
Who should use it
- General educational understanding of how creatinine clearance is estimated.
- A reference point ahead of discussing lab results with a healthcare provider.
Industry applications
- Health education
- Clinical reference (informational only)
Advantages
- Uses a well-established, widely referenced formula.
- Requires only common lab and demographic inputs.
Limitations
- Older formula than some modern clinical standards, and not a substitute for professional medical evaluation.
Common mistakes to avoid
- Treating this estimate as equivalent to a clinical lab-reported eGFR, which may use a different, more current formula.
- Using this tool to self-diagnose kidney problems instead of consulting a healthcare provider.
Best practices
- Always discuss actual lab results and kidney function with your doctor, who can interpret them alongside your full medical history.
Tips
- Always bring your actual estimated GFR or creatinine clearance results to your doctor for proper interpretation — trends over time usually matter more than a single reading.