What is GFR (Glomerular Filtration Rate)?

Glomerular Filtration Rate (GFR) is the best overall measure of kidney function. It is a calculation that estimates how much blood passes through the glomeruli—the tiny filters in your kidneys—each minute. A lower GFR value suggests that the kidneys are not cleaning your blood as effectively as they should be.

What is a normal GFR level by age?

While a GFR of 90 or above is considered normal for young adults, GFR naturally decreases with age. For example, a normal GFR for someone over 60 might be slightly lower. It's more important to monitor the trend of your GFR over time with your doctor. Generally, a GFR below 60 mL/min/1.73m² for three months or more is a sign of Chronic Kidney Disease (CKD).

Why doesn't this GFR calculator ask for race?

This calculator uses the 2021 CKD-EPI Creatinine Equation, which is the most current and recommended formula. Previous formulas included a race modifier for individuals identified as Black. This was removed because race is a social construct, not a biological one, and its inclusion created inaccuracies and health inequities. The 2021 formula provides a more precise and unbiased estimation for everyone.

Can I improve my GFR score?

Yes, in many cases you can protect your remaining kidney function and prevent your GFR from falling further. Key strategies include managing blood pressure, controlling blood sugar levels if you have diabetes, reducing salt intake, avoiding NSAID pain relievers, maintaining a healthy weight, and not smoking. Always consult a healthcare professional before making changes to your health regimen.

GFR Calculator

Quickly estimate your Glomerular Filtration Rate (eGFR) to assess your kidney function using the latest 2021 CKD-EPI formula.

Serum Creatinine

Age

Biological Sex

Male Female

Your Guide to Glomerular Filtration Rate (GFR)

Your Glomerular Filtration Rate (GFR) is the best measure of your kidney health. Think of your kidneys as a sophisticated filtration system. They contain millions of tiny filters called glomeruli that clean waste from your blood. The GFR number estimates how much blood these filters clean each minute. A low GFR may mean your kidneys are not working at full capacity.

This calculator provides an estimated GFR (eGFR) using the 2021 CKD-EPI Creatinine Equation. This is the most current formula recommended by the National Kidney Foundation for its improved accuracy and equity.

Anatomical illustration of human kidneys showing the renal artery and vein.

How to Use This GFR Calculator in 3 Simple Steps

Enter Serum Creatinine: Find this value on your recent blood test report. Enter the number and choose the correct unit (mg/dL is common in the U.S., while μmol/L is standard in many other countries).
Enter Your Details: Input your age in years and your biological sex assigned at birth.
Get Your Result: Click "Calculate GFR" to see your eGFR score and the corresponding stage of Chronic Kidney Disease (CKD).

Important Medical Disclaimer

This tool is for informational purposes only and does not constitute medical advice. Your eGFR result is an estimate. It should be interpreted by a qualified healthcare professional who can consider your complete medical history. Do not make any changes to your treatment or lifestyle without first consulting your doctor.

What Your GFR Result Means

Your GFR number helps your doctor determine your stage of chronic kidney disease (CKD). Here's a quick breakdown:

GFR 60 or higher: Generally considered in the normal range, though it's important to monitor if you have other risk factors like diabetes, high blood pressure, or a family history of kidney disease.
GFR below 60: May indicate kidney disease. A result in this range for three months or more confirms a diagnosis of CKD.
GFR below 15: Indicates kidney failure, a serious condition that requires urgent medical attention, often involving dialysis or a kidney transplant.

The Modern GFR Formula: Why Race is No Longer a Factor

You may have used older GFR calculators that required you to specify if you are Black. This calculator does not. The 2021 CKD-EPI formula removed the race coefficient after extensive research showed it was not biologically justified and created a significant barrier to equitable healthcare. By using this new, race-free equation, we provide a more accurate and unbiased estimation of kidney function for every individual.

How to Protect Your Kidneys and Improve GFR

While some GFR decline is normal with age, you can take proactive steps to protect your kidney health. Managing risk factors is the most effective strategy. The leading causes of CKD are diabetes and high blood pressure.

Control Blood Pressure: Aim for a blood pressure below 120/80.
Manage Blood Sugar: If you have diabetes, keep your blood glucose levels in your target range.
Reduce Salt Intake: A lower-sodium diet can help manage blood pressure.
Maintain a Healthy Weight: Being overweight increases the workload on your kidneys. Our BMI Calculator can help you assess your weight status.
Be Smart About Medications: Avoid overuse of non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen.
Don't Smoke: Smoking damages blood vessels, reducing blood flow to the kidneys.