Smart Calculator

GFR Calculator

GFR Calculator

Calculate your estimated Glomerular Filtration Rate (eGFR) to assess kidney function for adults and children using clinically validated formulas.

Kidney Function Assessment
Enter patient information to calculate estimated GFR and CKD stage

Normal range: 0.6-1.2 mg/dL (varies by lab)

Understanding GFR & CKD Stages

CKD Stages

G1: ≥90Normal
G2: 60-89Mildly decreased
G3a: 45-59Mild-moderate
G3b: 30-44Moderate-severe
G4: 15-29Severe
G5: <15Kidney failure

Formula Comparison

CKD-EPI 2021:

Most current, race-free formula recommended by guidelines

MDRD:

Traditional formula, may underestimate at higher GFR levels

Schwartz Formula:

Pediatric formula for children aged 0-17 years

Clinical Significance

  • Normal GFR: 90-120 mL/min/1.73 m² in healthy adults
  • CKD diagnosis: GFR <60 for ≥3 months
  • Referral to nephrology: Usually at GFR <30
  • Dialysis consideration: GFR <15 or symptomatic

Limitations

  • Less accurate in extremes of age, body size, or muscle mass
  • May be inaccurate in acute kidney injury
  • Requires stable creatinine levels
  • Consider cystatin C-based equations for better accuracy