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This is an estimate for education only, not a diagnosis. Only a clinician can interpret kidney function. Talk to your doctor about any result.
This tool is for general education only and is not medical advice. Talk to a healthcare professional about your results.
Estimated glomerular filtration rate (eGFR) is one of the main numbers doctors use to check how well your kidneys are working. It reflects how effectively your kidneys filter waste from your blood, and it is calculated from a simple blood test.
What eGFR measures
Your kidneys contain millions of tiny filters that clear waste and extra fluid from your blood. The glomerular filtration rate is the volume of blood those filters clean each minute. Because it cannot be measured directly in routine care, it is estimated from your blood creatinine level together with your age and sex.
The CKD-EPI 2021 equation
This tool uses the CKD-EPI 2021 equation, the current standard recommended for estimating GFR in adults. It is a race-free formula, meaning it no longer uses race as a variable, which is now the preferred approach. Results are reported adjusted to a standard body size.
How results are grouped
In general, an eGFR of 90 or above is considered normal, and lower values are grouped into stages that may indicate reduced kidney function. However, a single result is only a snapshot, and factors such as hydration, muscle mass, and recent meals can affect creatinine.
This tool is for general education only and is not a diagnosis. Only a healthcare professional can interpret your kidney function in the full context of your health. Always discuss lab results with your doctor.
Frequently asked questions
What is GFR?
Glomerular filtration rate measures how well your kidneys filter waste from your blood. Estimated GFR, or eGFR, is calculated from a blood creatinine test along with your age and sex.
What is a normal eGFR?
An eGFR of 90 or above is generally normal, while lower values may indicate reduced kidney function. Only a clinician can interpret your result in context.
Which equation does this use?
It uses the CKD-EPI 2021 equation, which is race-free and is the current standard recommended for estimating GFR in adults.
Is this a diagnosis?
No. This is an educational estimate. Kidney health depends on many factors, and only a healthcare professional can diagnose or interpret it.
Sources
Reviewed against these authoritative references. Last updated August 2026.
- National Kidney Foundation. Estimated Glomerular Filtration Rate (eGFR)
- National Kidney Foundation. GFR Calculator (KDOQI)
- National Institute of Diabetes and Digestive and Kidney Diseases (NIH). Chronic Kidney Disease Tests & Diagnosis
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