GFR Calculator
Estimate your glomerular filtration rate (GFR) to assess your kidney function. This medical tool provides results based on the CKD-EPI formula.
GFR Calculation
Calculating your GFR…
GFR Calculation Results
Kidney Disease Stages
Chronic Kidney Disease (CKD) is divided into five stages based on the GFR value. Understanding your stage can help guide treatment and management decisions.
| Stage | GFR Level (mL/min/1.73m²) | Description | Action |
|---|---|---|---|
| Stage 1 | ≥ 90 | Normal or high kidney function | Monitor and manage risk factors |
| Stage 2 | 60-89 | Mildly decreased kidney function | Monitor and slow progression |
| Stage 3a | 45-59 | Mildly to moderately decreased kidney function | Evaluate and treat complications |
| Stage 3b | 30-44 | Moderately to severely decreased kidney function | Refer to nephrologist |
| Stage 4 | 15-29 | Severely decreased kidney function | Prepare for kidney replacement therapy |
| Stage 5 | < 15 | Kidney failure | Kidney replacement therapy (dialysis or transplant) |
Frequently Asked Questions
Glomerular Filtration Rate (GFR) is a test used to check how well your kidneys are working by estimating how much blood passes through the glomeruli (tiny filters in the kidneys) each minute. GFR is the best overall index of kidney function. It’s important because it helps doctors determine the stage of kidney disease, guide treatment decisions, and monitor disease progression over time.
GFR is calculated using formulas that take into account serum creatinine level, age, sex, and race. The most commonly used formula is the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation, which is more accurate than the older MDRD equation, especially at higher GFR levels. Our calculator uses the CKD-EPI formula to provide the most accurate estimate of kidney function.
GFR results are used to determine the stage of kidney disease. A GFR of 90 or above is considered normal (Stage 1). Values between 60-89 indicate mild kidney damage (Stage 2). GFR between 30-59 suggests moderate kidney damage (Stage 3). Values between 15-29 indicate severe kidney damage (Stage 4), and a GFR below 15 indicates kidney failure (Stage 5). The lower your GFR, the more severe the kidney damage and the more important it is to manage the condition properly.
The frequency of GFR testing depends on your kidney function and other risk factors. If you have normal kidney function (Stage 1) and no risk factors, testing every 1-2 years may be sufficient. For those with mild kidney disease (Stage 2), testing every 6-12 months is recommended. For moderate to severe kidney disease (Stages 3-4), testing every 3-6 months is typical. For kidney failure (Stage 5), more frequent monitoring is necessary. Your doctor will recommend the appropriate testing schedule based on your individual situation.
While it’s not always possible to significantly improve GFR in advanced kidney disease, you can often slow the progression of kidney disease and maintain your current GFR. Key strategies include controlling blood pressure and diabetes (if applicable), following a kidney-friendly diet, staying hydrated, avoiding NSAIDs and other nephrotoxic medications, not smoking, and maintaining a healthy weight. In early stages, these measures can sometimes lead to modest improvements in GFR. Always consult with your healthcare provider for personalized advice.