What is GFR?
Glomerular Filtration Rate (GFR) measures how well your kidneys filter waste from the blood each minute. It's the gold standard for assessing kidney function and staging Chronic Kidney Disease (CKD).
Clinically Referenced · CKD-EPI 2021
GFR Calculator
Estimate your Glomerular Filtration Rate (eGFR) instantly. Know your kidney function stage with a validated clinical formula.
eGFR Calculator
Enter your lab values below to calculate your estimated GFR.
Your eGFR
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mL/min/1.73m²
⚠ This tool is for educational purposes only. Always consult a qualified healthcare provider for medical advice.
Understanding Your eGFR
CKD-EPI 2021 Equation
This calculator uses the CKD-EPI 2021 equation—the current clinical standard recommended by KDIGO guidelines. It uses serum creatinine, age, and sex for an accurate, race-free estimate.
CKD Stages
eGFR values are categorized into G1 (normal, ≥90) through G5 (kidney failure, <15). Early detection of reduced eGFR enables timely intervention to slow kidney disease progression.
eGFR Reference Ranges
| Stage | eGFR (mL/min/1.73m²) | Description | Kidney Function |
|---|---|---|---|
| G1 | ≥ 90 | Normal or High | Normal |
| G2 | 60 – 89 | Mildly Decreased | Mildly Reduced |
| G3a | 45 – 59 | Mild to Moderate | Moderately Reduced |
| G3b | 30 – 44 | Moderate to Severe | Significantly Reduced |
| G4 | 15 – 29 | Severely Decreased | Severely Reduced |
| G5 | < 15 | Kidney Failure | Kidney Failure |
Frequently Asked Questions
What is a normal GFR value?
A normal GFR is 90 mL/min/1.73m² or higher (CKD Stage G1). Values between 60–89 indicate mildly reduced function (G2), and below 15 indicate kidney failure (G5). Values naturally decline slightly with age even in healthy individuals.
Which formula does this calculator use?
This tool uses the CKD-EPI 2021 equation, which is the current standard recommended by KDIGO (Kidney Disease: Improving Global Outcomes). It provides accurate eGFR estimates without requiring race as a variable.
Is eGFR the same as GFR?
Not exactly. eGFR is an estimate of GFR calculated from a blood creatinine test. Direct GFR measurement requires complex procedures, so eGFR is used in clinical practice as a reliable proxy.
What can lower my GFR?
GFR can be reduced by diabetes, high blood pressure, kidney infections, certain medications, dehydration, and aging. Some acute illnesses can also temporarily lower GFR. Consult your doctor if your eGFR is below 60 on repeated tests.
Can I improve my GFR?
In some cases, yes. Treating underlying causes like hypertension or diabetes, staying hydrated, avoiding nephrotoxic drugs, and maintaining a kidney-friendly diet can help preserve or slightly improve GFR. Learn more in our blog post on eGFR.
Learn More About Kidney Health
Read our in-depth guides on understanding eGFR, CKD stages, and how to protect your kidney function.