GFR Calculator
Calculate estimated glomerular filtration rate (eGFR) for kidney function assessment.
Your Information
Enter your information to calculate your estimated glomerular filtration rate (eGFR) with detailed analysis and charts.
Estimated GFR (eGFR)
0
mL/min/1.73m²
CKD-EPI
0
MDRD
0
Stage
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eGFR Scale
Formulas Comparison
CKD Stages
Your eGFR Value
Chronic Kidney Disease Stages
| Stage | eGFR Range | Description |
|---|---|---|
| Stage 1 | ≥ 90 | Normal or high kidney function |
| Stage 2 | 60-89 | Mildly decreased kidney function |
| Stage 3a | 45-59 | Mildly to moderately decreased kidney function |
| Stage 3b | 30-44 | Moderately to severely decreased kidney function |
| Stage 4 | 15-29 | Severely decreased kidney function |
| Stage 5 | < 15 | Kidney failure |
Complete User Guide
What is GFR?
GFR (Glomerular Filtration Rate) is a measure of how well your kidneys are filtering waste from your blood. It represents the rate at which fluid is filtered through the glomeruli (tiny filters in the kidneys) per unit of time.
eGFR (estimated GFR) is calculated using formulas that take into account your creatinine level, age, gender, and race. It's expressed in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73m²).
Why GFR is Important
GFR is the best overall indicator of kidney function. It helps healthcare providers:
- Detect kidney disease early
- Monitor kidney function over time
- Determine the stage of chronic kidney disease (CKD)
- Make decisions about treatment and medication dosing
- Assess the risk of kidney disease progression
How to Use This Calculator
- Enter your age (18-100 years)
- Select your gender (male or female)
- Select your race (used for formula adjustment)
- Choose your creatinine unit (mg/dL or μmol/L)
- Enter your serum creatinine level from your blood test
- Click 'Calculate eGFR' to see your results
- Review your eGFR value, CKD stage, and kidney function assessment
Understanding Your Results
eGFR Value
Your estimated glomerular filtration rate in mL/min/1.73m². Higher values indicate better kidney function. Normal eGFR is typically 90 or higher.
CKD Stage
Your chronic kidney disease stage based on your eGFR value. Stages range from Stage 1 (normal/high) to Stage 5 (kidney failure).
CKD-EPI vs MDRD
The calculator shows results from both formulas. CKD-EPI is the preferred formula as it's more accurate, especially at higher eGFR levels. MDRD is shown for comparison.
Chronic Kidney Disease Stages Explained
Stage 1 (eGFR ≥ 90)
Normal or high kidney function. May have kidney damage but function is preserved. Regular monitoring recommended.
Stage 2 (eGFR 60-89)
Mildly decreased kidney function. Kidney damage with mild loss of function. Monitoring and lifestyle changes recommended.
Stage 3a (eGFR 45-59)
Mildly to moderately decreased kidney function. More frequent monitoring and may need to see a nephrologist.
Stage 3b (eGFR 30-44)
Moderately to severely decreased kidney function. Regular nephrologist visits and treatment planning recommended.
Stage 4 (eGFR 15-29)
Severely decreased kidney function. Preparation for kidney replacement therapy (dialysis or transplant) should begin.
Stage 5 (eGFR < 15)
Kidney failure. Dialysis or kidney transplant is typically needed. Also called end-stage renal disease (ESRD).
eGFR Formulas Explained
CKD-EPI Formula
The preferred formula for calculating eGFR. More accurate than MDRD, especially at higher eGFR levels (above 60). Recommended by most medical organizations.
Takes into account: Creatinine, age, gender, and race
MDRD Formula
An older formula still used for comparison. Less accurate at higher eGFR levels but useful for historical comparison.
Takes into account: Creatinine, age, gender, and race
Factors Affecting GFR
Age: GFR naturally decreases with age. Normal decline is about 1 mL/min/1.73m² per year after age 40.
Gender: Men typically have higher muscle mass and creatinine levels, which affects the calculation.
Race: The formulas include race adjustments based on research showing differences in muscle mass and creatinine production.
Creatinine Level: Higher creatinine levels indicate reduced kidney function, as kidneys are less able to filter waste from the blood.
Muscle Mass: People with higher muscle mass produce more creatinine, which can affect eGFR calculations.
Important Notes
- eGFR is an estimate. Actual GFR can only be measured directly through specialized tests. The calculator provides estimates based on standard formulas.
- eGFR may not be accurate for certain populations, including children, pregnant women, people with very high or low muscle mass, or those with rapidly changing kidney function.
- A single eGFR measurement may not be diagnostic. Healthcare providers typically look at trends over time and consider other factors like protein in urine.
- This calculator is for educational and informational purposes only. Always consult with healthcare providers for accurate kidney function assessment, diagnosis, and treatment decisions.