GFR Calculator
Calculate your Glomerular Filtration Rate (GFR) to assess kidney function. This calculator provides results using standard formulas for both adults (CKD-EPI) and children (Schwartz formula). GFR is the best test to measure your level of kidney function and determine your stage of kidney disease.
CKD-EPI Formula Result: Your kidney function appears to be within normal range.
GFR ≥ 90 mL/min/1.73m² indicates normal kidney function or stage 1 CKD if kidney damage is present.
≥90
60-89
45-59
30-44
15-29
<15
Understanding GFR Results
📊 GFR Stages
- Stage 1: Normal kidney function (GFR ≥ 90) with kidney damage
- Stage 2: Mild loss (GFR 60-89) with kidney damage
- Stage 3a: Mild to moderate loss (GFR 45-59)
- Stage 3b: Moderate to severe loss (GFR 30-44)
- Stage 4: Severe loss (GFR 15-29)
- Stage 5: Kidney failure (GFR < 15)
🧪 About GFR Testing
- GFR estimates how much blood passes through glomeruli each minute
- Glomeruli are tiny filters in kidneys that remove waste
- Calculated using serum creatinine, age, sex, and body size
- Results standardized to body surface area (1.73m²)
- More accurate than creatinine alone for kidney assessment
👶 Pediatric Considerations
- Schwartz formula used for children ages 1-18 years
- GFR = (k × Height) / Serum Creatinine
- k is constant: 0.45 for infants, 0.55 for children, 0.70 for adolescent males
- Normal values change as children grow
- Requires height measurement for accurate calculation
Important Note: This calculator provides estimates only. GFR calculations have limitations and may not be accurate for all individuals (e.g., extremely muscular, amputees, severely malnourished). Actual kidney function assessment requires comprehensive evaluation by a nephrologist. Always consult with a healthcare professional for medical advice.