GFR Calculator – Check Kidney Function Instantly
The GFR Calculator (Glomerular Filtration Rate Calculator) is a tool used to estimate how well your kidneys are functioning. It helps detect early stages of kidney disease by analyzing creatinine levels, age, gender, and body parameters.
What is GFR (Glomerular Filtration Rate)?
GFR is a measure of how efficiently your kidneys filter blood. A lower GFR indicates reduced kidney function, and chronic kidney disease (CKD) stages are classified based on GFR levels.
GFR Calculator Formulas
The most commonly used GFR estimation equations are:
1. CKD-EPI Equation
GFR = 141 × min(Scr/κ,1)^α × max(Scr/κ,1)^-1.209 × 0.993^Age × [1.018 if female] × [1.159 if Black]
2. MDRD Equation
GFR = 175 × (Scr)^-1.154 × (Age)^-0.203 × [0.742 if female] × [1.212 if Black]
3. Cockcroft-Gault Formula
GFR = [(140 - age) × weight (kg)] / (72 × Scr) × [0.85 if female]
Example Calculation
Input: Male, 40 years old, 75 kg, serum creatinine = 1.2 mg/dL
GFR (Cockcroft-Gault): GFR = (140 - 40) × 75 / (72 × 1.2) = 86.8 mL/min
How to Use the GFR Calculator
- Enter your age, gender, weight, and serum creatinine level
- Select the formula (CKD-EPI, MDRD, or Cockcroft-Gault)
- Click "Calculate"
- Get your estimated GFR value and interpretation
GFR and CKD Stages
- Stage 1: GFR ≥ 90 (normal)
- Stage 2: GFR 60–89 (mild decrease)
- Stage 3a: GFR 45–59 (mild to moderate)
- Stage 3b: GFR 30–44 (moderate to severe)
- Stage 4: GFR 15–29 (severe)
- Stage 5: GFR < 15 (kidney failure)
Who Should Use This Calculator?
- Patients with diabetes, hypertension, or kidney conditions
- Doctors and nephrologists
- Lab technicians and clinical researchers
Benefits of the GFR Calculator
- Early detection of kidney damage
- Tracks CKD progression
- Supports clinical decision-making
- Free and easy-to-use interface
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FAQs About GFR Calculator
1. What is a normal GFR?
Normal GFR is generally above 90 mL/min/1.73m² for healthy individuals.
2. What factors affect GFR?
Age, sex, race, muscle mass, and serum creatinine levels affect GFR.
3. Which formula should I use?
CKD-EPI is the most accurate and recommended by guidelines. Cockcroft-Gault is still widely used in drug dosing.
4. Can GFR improve over time?
Yes, with lifestyle changes and proper treatment, GFR may improve if the underlying cause is addressed.
5. Is this calculator suitable for children?
No, pediatric GFR should be calculated using child-specific equations like the Schwartz formula.