eGFR CKD-EPI 2021 Calculator

About this calculator

eGFR (estimated glomerular filtration rate) is the primary lab-based measure of kidney function, and the 2021 CKD-EPI creatinine equation is the current standard formula recommended by the National Kidney Foundation and American Society of Nephrology to calculate it from a routine blood test. It replaced the 2009 CKD-EPI equation specifically to remove the race coefficient that had been applied for Black patients, after evidence showed race-based adjustment was not a reliable biological proxy and could delay care; the 2021 version uses only serum creatinine, age, and sex, applying different constants (kappa, alpha) and a minimum/maximum term structure depending on whether creatinine falls above or below a sex-specific threshold.

The resulting eGFR, in mL/min/1.73m², is then mapped to a CKD stage under KDIGO guidelines — G1 (normal, eGFR 90+) through G5 (kidney failure, below 15) — which nephrologists and primary care physicians use to stage chronic kidney disease, guide referral timing, and adjust medication dosing. This tool is for education only and does not replace a clinical lab result or physician interpretation.