eGFR calculator (CKD-EPI 2021, race-free)

eGFR estimates kidney filtration in mL/min/1.73 m² from standardized serum creatinine (mg/dL), and optionally cystatin C (mg/L), with age and sex. The NIDDK and NKF recommend the 2021 race-free equations; using creatinine and cystatin C together is more accurate.

2021 creatinine: 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [female]
  κ = 0.7 (female), 0.9 (male); α = −0.241 (female), −0.302 (male)
2012 cystatin C: 133 × min(Scys/0.8, 1)^−0.499 × max(Scys/0.8, 1)^−1.328 × 0.996^age × 0.932 [female]
2021 creatinine–cystatin C: 135 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−0.544 × min(Scys/0.8, 1)^−0.323
  × max(Scys/0.8, 1)^−0.778 × 0.9961^age × 0.963 [female];  α = −0.219 (female), −0.144 (male)
Creatinine µmol/L ÷ 88.4 = mg/dL

KDIGO GFR categories: G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15 mL/min/1.73 m².

Assumptions and limits

• Adults only, with stable kidney function: not valid in acute kidney injury, and less accurate with extreme muscle mass, amputations, pregnancy or high-protein diets.
• An eGFR alone does not diagnose chronic kidney disease, and this page does not adjust any medicine dose.

Worked example

A 50-year-old woman with creatinine 1.0 mg/dL (88 µmol/L): 142 × (1.0/0.7)^−1.2 × 0.9938^50 × 1.012 = 69 mL/min/1.73 m², category G2.

References

• NIDDK: eGFR equations for adults
• Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–1749
• National Kidney Foundation: CKD-EPI creatinine–cystatin equation (2021)
• KDIGO 2024 guideline for the evaluation and management of CKD