eGFR Calculator (CKD-EPI 2021)

How it works

eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 (if female); κ = 0.7 (F) / 0.9 (M); α = −0.241 (F) / −0.302 (M)

The estimated glomerular filtration rate is a stand-in for how much blood your kidneys clean per minute, scaled to a standard body size of 1.73 m². The 2021 CKD-EPI creatinine equation is the current US standard and, unlike the older version, uses no race coefficient. It takes serum creatinine — a waste product the kidneys filter — together with age and sex, applies sex-specific constants (κ and α), and produces a number in mL/min/1.73m². KDIGO then maps that number onto stages G1 through G5. Creatinine depends on muscle mass, so the estimate is least reliable at the extremes of body build.

Worked example

A 50-year-old man with a serum creatinine of 1.0 mg/dL: Scr/κ = 1.0 ÷ 0.9 = 1.111, so eGFR = 142 × 1^−0.302 × 1.111^−1.200 × 0.9938^50 ≈ 92 mL/min/1.73m² — squarely in stage G1, normal kidney function.

Sources: NKF/ASN CKD-EPI 2021 creatinine equation · KDIGO CKD staging

Frequently asked questions