eGFR Calculator (CKD-EPI 2021)
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The eGFR Calculator estimates kidney function using the CKD-EPI 2021 (race-free) creatinine equation. Enter age, sex and serum creatinine in mg/dL or µmol/L; the tool returns eGFR (mL/min/1.73 m²) and a CKD stage from G1 (normal/high) to G5 (kidney failure).
eGFR is an estimate; clinical interpretation may incorporate albumin-to-creatinine ratio (ACR), trend over time, blood pressure and other markers. For drug dosing, some contexts use de-indexed GFR; see our BSA calculator for body size estimates.
FAQ
- Which formula is used?
CKD-EPI 2021 creatinine (race-free), with sex-specific constants and an age factor. - What units can I enter?
mg/dL or µmol/L (1 mg/dL = 88.4 µmol/L). The calculator converts automatically. - How are CKD stages defined?
G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15 (mL/min/1.73 m²). - How accurate is eGFR?
It’s an estimate; hydration status, lab variation and body composition can shift results. Use trends and clinical guidance. - Do I need albuminuria (ACR)?
ACR refines risk category and prognosis but isn’t captured here; follow your provider’s testing schedule.
Disclaimer
This calculator is for educational purposes and is not a diagnostic tool. Kidney health decisions require interpretation by a qualified clinician.
References
- National Kidney Foundation (NKF) – GFR Calculator and CKD-EPI Equations
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – CKD-EPI Creatinine (2021) Equation
- Inker LA et al. (2021) – New Creatinine-Based Equation for Estimating GFR Without Race — New England Journal of Medicine
- Kidney Disease: Improving Global Outcomes (KDIGO) – Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
- Centers for Disease Control and Prevention (CDC) – Chronic Kidney Disease Basics
- World Health Organization (WHO) – Kidney Disease Fact Sheet (2024)
- Levey AS et al. (2019) – GFR Decline as an End Point for Clinical Trials in CKD: A Scientific Workshop Sponsored by the NKF and FDA — American Journal of Kidney Diseases