Free GFR Calculator
Estimate your GFR (glomerular filtration rate, often called eGFR) using the current 2021 CKD-EPI race-free equation — the same formula recommended by the National Kidney Foundation and American Society of Nephrology, and the one most U.S. labs now use.
Enter your values
Estimated GFR
This calculator is for general educational purposes and is not a diagnosis. It does not apply to children, pregnancy, acute kidney injury, or very high/low muscle mass. Always use your lab's reported eGFR and discuss any result with your doctor or nephrologist.
What does your result mean?
eGFR is reported in mL/min/1.73m² and is used to classify chronic kidney disease (CKD) into stages:
- 90+: Normal or high (Stage 1 if other kidney damage is present)
- 60–89: Mildly reduced (Stage 2)
- 45–59: Mild to moderate reduction (Stage 3a)
- 30–44: Moderate to severe reduction (Stage 3b)
- 15–29: Severe reduction (Stage 4)
- Below 15: Kidney failure range (Stage 5)
Read more in our full chronic kidney disease guide and CKD stages explained.
Why this calculator uses the 2021 equation
For years, the standard eGFR formula applied a race-based adjustment for Black patients. In 2021, a joint task force from the National Kidney Foundation and American Society of Nephrology recommended removing it, after finding it wasn't biologically justified and could delay appropriate diagnosis and referral for Black patients. This calculator uses that current, race-free 2021 CKD-EPI equation.
Frequently asked questions
What is a GFR calculator?
A GFR calculator estimates your kidney filtration rate (eGFR) using a formula that combines your serum creatinine blood test result with your age and sex. It gives an estimate, not a diagnosis.
What formula does this GFR calculator use?
This calculator uses the 2021 CKD-EPI creatinine equation, the race-free formula currently recommended by the National Kidney Foundation and American Society of Nephrology, and endorsed by KDIGO.
Is an online GFR calculator as accurate as a lab result?
An online calculator uses the same equation labs use, but your lab's reported eGFR is based on your actual creatinine result from that specific test and is the one your doctor will use. Use this tool for general understanding, not as a replacement for your lab report.
Why does the calculator ask for sex but not race?
The current 2021 CKD-EPI equation removed the previous race-based coefficient after a joint task force found it was not biologically justified and could delay appropriate care. Sex is still used because it affects average muscle mass and creatinine production.
Have questions about your result?
Nisarg Ayurveda offers a free consultation to discuss complementary Ayurvedic wellness support alongside your medical care. Bring your recent lab results if you have them.