eGFR Calculator
Assess Kidney Function (NKF Recommended)
mg/dl
mg/L

ResultsmL/min/1.73m²

CKD-EPI Creatinine (2021)

Standard Formula

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Kidney Failure Risk & Staging

Required for accurate staging (G+A)

Enter ACR above to see detailed Risk Classification and Staging.

About GFR and CKD-EPI 2021

Glomerular filtration rate (GFR) is the best overall index of kidney function. Normal GFR varies according to age, sex, and body size, and declines with age.

The **National Kidney Foundation (NKF)** and the American Society of Nephrology (ASN) Task Force (2021) recommends using the **CKD-EPI Creatinine Equation (2021)** to estimate GFR. This new equation does not include a race coefficient.

Interpreting Results

  • GFR > 90: Normal or high (Stage G1 if kidney damage present)
  • GFR 60-89: Mildly decreased (Stage G2)
  • GFR 30-59: Moderately decreased (Stage G3a-G3b)
  • GFR 15-29: Severely decreased (Stage G4)
  • GFR < 15: Kidney failure (Stage G5)

Note: eGFR is an estimate. Clinical context is required. "Is it CKD?" Logic requires persistence of abnormalities for ≥ 3 months.

Clinical Note

Standardized Assays: This calculator assumes the use of standardized creatinine assays (IDMS-traceable), which are standard in most modern labs.

Confirmatory Tests: Cystatin C can be used as a confirmatory test if eGFR based on creatinine is less reliable (e.g., unusual muscle mass, diet).