GFR Calculator
Calculate your estimated Glomerular Filtration Rate (eGFR) using the CKD-EPI 2021 race-free formula to assess kidney function.
eGFR (mL/min/1.73m²)
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CKD Stage
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Interpretation
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What is GFR Calculator?
The eGFR (estimated Glomerular Filtration Rate) calculator uses the CKD-EPI 2021 race-free equation to estimate how well your kidneys are filtering waste from your blood. It is the standard tool used by nephrologists to stage chronic kidney disease (CKD).
How to use
- 1 Enter your serum creatinine level in mg/dL (from a blood test).
- 2 Enter your age in years.
- 3 Select your biological sex.
- 4 Click Calculate to get your eGFR result.
- 5 Review your CKD stage and interpretation in the results panel.
Formula
Example calculation
A 55-year-old female with serum creatinine of 1.1 mg/dL: eGFR = 142 × (1.1/0.7)^−1.200 × (0.9938)^55 × 1.012 ≈ 57 mL/min/1.73m² (CKD Stage 3a).
Frequently asked questions
What is a normal eGFR?
An eGFR of 90 or above is considered normal kidney function. Values between 60–89 suggest mildly reduced function, while values below 60 indicate chronic kidney disease of varying severity.
What is the CKD-EPI 2021 formula?
CKD-EPI 2021 is the current standard race-free equation endorsed by kidney disease guidelines. It removed the race coefficient from earlier versions to reduce health disparities in CKD diagnosis.
What does CKD Stage 3 mean?
CKD Stage 3 (eGFR 30–59) indicates moderately reduced kidney function. Stage 3a is 45–59 and Stage 3b is 30–44. At this stage, monitoring and lifestyle changes are important to slow progression.
Can eGFR fluctuate?
Yes. eGFR can vary day to day based on hydration, diet, medications, and physical activity. A single result should be confirmed with repeat testing before making clinical decisions.
Should I see a doctor if my eGFR is low?
Yes. An eGFR below 60 that persists for more than 3 months indicates CKD and warrants evaluation by a healthcare provider or nephrologist.