GFR Calculator (Estimated Glomerular Filtration Rate)
The Glomerular Filtration Rate (GFR) is the best overall measure of kidney function. This calculator uses the CKD-EPI 2021 equation (race-free version) to estimate your GFR from serum creatinine, age, and gender, and provides your CKD (Chronic Kidney Disease) stage.
The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation is the current standard for estimating GFR. It replaced the earlier CKD-EPI 2009 equation that included a race coefficient, which has been removed to reduce health disparities. The formula uses serum creatinine (a waste product from muscle metabolism filtered by the kidneys), age, and gender to estimate how efficiently your kidneys filter blood.
A normal GFR is approximately 90–120 mL/min/1.73m². Values below 60 sustained for 3 or more months indicate chronic kidney disease. CKD is classified into 5 stages (G1–G5) based on eGFR level, with additional albuminuria categories (A1–A3) providing further risk stratification. Early stages are often asymptomatic, making regular screening important for at-risk populations (diabetes, hypertension, family history of kidney disease).
This calculator provides estimates for informational purposes. eGFR from creatinine can be affected by muscle mass, diet, medications, and acute illness. Cystatin C-based eGFR equations may be more accurate in certain populations. Always discuss your results with a healthcare provider.