The CKD-EPI 2021 Equation

This GFR calculator implements the 2021 race-free CKD-EPI equation: eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.2 × 0.9938^Age × 1.012 (if female), with κ and α set by sex. It replaced older equations that incorporated race, which overstated kidney function in Black patients.

Reading the Stages

KDIGO stages run G1 (≥ 90, normal) through G5 (under 15, kidney failure). The GFR threshold at 60 mL/min distinguishes mild loss from chronic kidney disease, and values below 30 warrant nephrology referral.

Interpreting with Care

eGFR is an estimate, not a measurement. It dips temporarily with dehydration, high protein intake, and certain medications, and rises in pregnancy and with muscle mass. Interpret trends over time with your care team, not single numbers.