Estimate your glomerular filtration rate using the CKD-EPI 2021 equation to assess kidney function.
The Estimated Glomerular Filtration Rate (eGFR) is a critical marker used to assess how effectively your kidneys are filtering waste products from your blood. By using your serum creatinine levels—a byproduct of muscle metabolism—alongside your age and biological sex, this calculator estimates the flow rate of filtered fluid through the kidney. Understanding your eGFR is essential because kidney function often declines gradually without obvious symptoms, making regular monitoring vital for early detection of potential concerns.
This measurement is particularly important for individuals with risk factors such as diabetes, high blood pressure, or a family history of renal issues. A normal eGFR typically suggests healthy kidney function, while lower values may indicate various stages of chronic kidney disease (CKD). It is important to recognize that this tool provides an estimate based on standardized formulas and does not constitute a medical diagnosis. It is intended to help you understand your lab results and facilitate informed discussions with your healthcare professional, who will consider your full medical history and other diagnostic tests.
Type in your own measurements — the grey hints are just examples.
Enter in mg/dL. If your result is in µmol/L, divide by 88.4.
To calculate your eGFR, you will need a recent blood test result showing your serum creatinine level. Most laboratories report this in mg/dL or µmol/L; this calculator specifically requires mg/dL (if your result is in µmol/L, you can convert it by dividing by 88.4). You will also need to enter your current age and biological sex, as these factors are used to adjust the estimate for typical muscle mass variations.
Accuracy is highest when using a result from a steady-state period. For instance, avoid taking the blood test immediately after intense exercise or while severely dehydrated, as these can temporarily affect creatinine levels. If you do not have a recent lab report, you should consult your doctor to order the appropriate metabolic panel.
The results of an eGFR test are typically reported in mL/min/1.73m². A value of 90 or higher is generally considered within the normal or high range (Stage G1), suggesting healthy kidney filtration. A result between 60 and 89 may indicate a mild reduction in function (Stage G2), which in many cases is a normal part of aging or requires simple monitoring rather than active intervention. However, when the eGFR remains below 60 for a period of three months or more, it often indicates Chronic Kidney Disease (CKD), as this threshold marks a point where kidney function is significantly enough reduced to impact long-term health.
Lower values are categorized into more specific stages: Stage G3a (45–59) represents a mild-to-moderate decline, while Stage G3b (30–44) indicates a moderate-to-severe decline. Values below 30 (Stage G4) represent a severe decline in filtration capacity, and a result below 15 (Stage G5) is associated with kidney failure, requiring urgent medical review and discussion of renal replacement therapies. The "1.73m²" in the unit refers to the average adult body surface area, which helps standardize results across different body sizes, though it may be less accurate for people who are significantly larger or smaller than average.
It is vital to note that a single eGFR reading can be influenced by transient factors. Acute dehydration, high-protein meals, or recent intense physical activity can temporarily raise creatinine levels and falsely lower your eGFR estimate. Certain medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) or specific antibiotics, can also impact results. Furthermore, the formula may be less accurate for individuals with muscle-wasting diseases or those using creatine supplements, as these factors directly alter serum creatinine levels regardless of kidney function. Because this calculator provides an estimate based on population averages, it is essential to review your results with a clinician. They will interpret the number alongside other markers, such as a urine albumin-to-creatinine ratio (uACR), to assess if protein is leaking into the urine, which is another key indicator of kidney health.
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Estimated Glomerular Filtration Rate (eGFR) is derived from a serum creatinine blood test and is the primary measure used to assess how well the kidneys are filtering waste from the blood. This calculator applies the CKD-EPI 2021 equation, the current standard recommended by nephrology guidelines for adults.
An eGFR of 90 or above is generally considered within the normal range for most adults, though values at the lower end may still warrant monitoring. Results between 60 and 89 may suggest mildly reduced kidney function. Values below 60 — especially if persistent — can be associated with chronic kidney disease at varying stages, and values below 30 may require prompt specialist review.
eGFR is an estimate influenced by muscle mass, diet, hydration, and certain medications. A single eGFR reading is rarely diagnostic on its own; trends over time and results alongside other kidney markers (such as urine albumin) provide a much fuller picture. This result is for educational reference only.
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An eGFR below 60 or a sudden drop from your previous result should be reviewed promptly with your doctor.
Sources & Methodology
These references support the formula, educational ranges, and interpretation used in this calculator. Results are estimates and are not a diagnosis.
Medical Disclaimer
This calculator and its accompanying content are provided for general educational and informational purposes only. They are not intended to be, and should not be used as, a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition or before making decisions about your health. Never disregard professional medical advice or delay seeking it because of information provided by this tool. Healio360 does not warrant the accuracy, completeness, or usefulness of this content and assumes no liability for actions taken based on it.