Estimate your Glomerular Filtration Rate (GFR), a measure of kidney function, using the MDRD formula. This is informational only — always consult a doctor for medical decisions.
This tool estimates Glomerular Filtration Rate (GFR), a key measure of kidney function, based on factors including serum creatinine level, age, sex, and sometimes race. GFR estimates are widely used by doctors to assess kidney health and stage chronic kidney disease.
This calculator commonly uses the CKD-EPI equation, the current standard formula recommended by major nephrology guidelines, which estimates GFR from serum creatinine, age, and sex. Results are expressed in mL/min/1.73m².
Enter your serum creatinine level (from a blood test), age, and sex, and the calculator estimates your GFR value.
Example: A GFR of 90 mL/min/1.73m² or above is generally considered normal kidney function, while values below 60 sustained over 3 months may indicate chronic kidney disease.
What is a normal GFR value? A GFR of 90 or above is generally considered normal, though normal ranges can vary somewhat with age, as kidney function naturally declines gradually over time.
What do lower GFR numbers mean? Lower GFR values indicate reduced kidney function, and doctors use specific thresholds (like below 60, 30, or 15) to classify the stage of chronic kidney disease.
Is this calculator a substitute for a doctor's diagnosis? No — this tool provides an estimate for informational purposes only. Kidney function assessment and diagnosis should always be confirmed and interpreted by a healthcare professional.
Why does age affect the GFR calculation? Kidney function naturally declines with age even in healthy individuals, so age is factored into the formula to provide a more accurate estimate relative to expected values for that age group.
What factors can affect creatinine levels besides kidney function? Muscle mass, diet (especially high meat intake), hydration status, and certain medications can all influence creatinine levels independent of actual kidney function, which is why GFR estimates are interpreted alongside clinical context.