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eGFR Formula Calculator (CKD-EPI 2021)
Want to see the actual eGFR formula and plug in your own numbers? This page uses the CKD-EPI 2021 creatinine equation: eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^Age × 1.012 (if female), where Scr is serum creatinine in mg/dL, κ is 0.7 for females and 0.9 for males, and α is −0.241 for females and −0.302 for males. The min/max structure creates a two-slope curve around the κ threshold, the 0.9938^Age term accounts for the fall in filtration with age, and the 1.012 factor adjusts for sex — with no race term, because the 2021 equation is race-free. Enter your creatinine (mg/dL or µmol/L), age and sex and the calculator evaluates the formula and maps the result to a KDIGO stage. A single eGFR is a screening estimate, not a diagnosis. Free, private, browser-only.
Formula: 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^Age × 1.012 (female)
- κ = 0.7 / 0.9 (F/M); α = −0.241 / −0.302 (F/M); Scr in mg/dL (µmol/L ÷ 88.42)
- KDIGO stages: G1 ≥90 · G2 60–89 · G3a 45–59 · G3b 30–44 · G4 15–29 · G5 <15
Frequently asked questions
What is the CKD-EPI 2021 eGFR formula?
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^Age × 1.012 (if female). Scr is serum creatinine in mg/dL; κ = 0.7 (female) or 0.9 (male); α = −0.241 (female) or −0.302 (male). There is no race coefficient — it is the race-free 2021 equation.
What do κ (kappa) and α (alpha) mean in the equation?
κ is a sex-specific creatinine scaling constant (0.7 female, 0.9 male). α is the exponent applied when creatinine is at or below κ (−0.241 female, −0.302 male). The min/max terms switch between the α slope below κ and a fixed −1.200 slope above it, giving the curve its shape.