GFR Calculator (CKD-EPI 2021)

GFR Calculator – Quick Cheat Sheet

Equation: CKD-EPI 2021 creatinine-only (race-free).
Formula: eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^Age × (1.012 if female).
κ: 0.7 (female), 0.9 (male). α: −0.241 (female), −0.302 (male).
Units: Scr may be entered in mg/dL or µmol/L (conversion: 1 mg/dL = 88.4 µmol/L).
Output: mL/min/1.73 m² (normalized to standard BSA).
Staging (by eGFR): G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15.
Note: Intended for adults; use clinical judgment and guidelines for interpretation.

Edge cases & notes

Abnormal muscle mass, diet, medications, or acute kidney injury can affect creatinine and eGFR accuracy.
For dosing (drug clearance), some clinicians prefer creatinine clearance estimates; this tool reports eGFR.
In pediatrics or pregnancy, other formulas apply; this implementation is adult-focused.