Your kidney function, in one number.
Enter your serum creatinine, age and sex and see your estimated glomerular filtration rate (eGFR) instantly, along with your CKD stage, where you sit on the G1 to G5 scale, and what the number means.
Your lab values
Your serum creatinine level from a blood test.
Your current age in years.
Biological sex affects the GFR calculation.
Race factor used in the MDRD formula.
This report computes eGFR with the CKD-EPI 2021 equation, which uses only creatinine, age and sex (no race factor), so the race selection does not change the result. Results update as you type, in mL/min/1.73m².
What your eGFR means
Where you sit on the GFR scale
The GFR thresholds that matter
CKD stages at a glance
The KDIGO staging system splits kidney function into six bands. The highlighted row is where your current eGFR falls.
| Stage | eGFR (mL/min/1.73m²) | Description |
|---|
GFR, explained
What is GFR?
Glomerular Filtration Rate (GFR) measures how well your kidneys filter waste from the blood. It is considered the best overall indicator of kidney function. A normal GFR is approximately 90-120 mL/min/1.73m². GFR naturally declines with age, decreasing about 1 mL/min per year after age 40.
How eGFR is Calculated
Estimated GFR (eGFR) is calculated using the MDRD (Modification of Diet in Renal Disease) equation: eGFR = 175 × (creatinine)^-1.154 × (age)^-0.203 × 0.742 (if female) × 1.212 (if African American). This formula uses serum creatinine from a simple blood test along with age, sex, and race.
Kidney Function Stages
Stage 1: GFR 90+ (normal function with other signs of kidney damage). Stage 2: GFR 60-89 (mild decrease). Stage 3a: GFR 45-59 (mild to moderate decrease). Stage 3b: GFR 30-44 (moderate to severe decrease). Stage 4: GFR 15-29 (severe decrease). Stage 5: GFR below 15 (kidney failure, dialysis may be needed).
Protecting Your Kidney Health
Maintain healthy blood pressure (below 130/80), control blood sugar if diabetic, stay hydrated, limit NSAID use, avoid excessive protein intake, do not smoke, and maintain a healthy weight. Regular screening is recommended if you have diabetes, high blood pressure, heart disease, or a family history of kidney disease.
Common questions
What is a normal GFR?
A normal GFR is 90-120 mL/min/1.73m² for healthy young adults. GFR naturally decreases about 1 mL/min per year after age 40. A GFR above 60 with no other signs of kidney damage is generally considered adequate function. Below 60 for 3 or more months indicates chronic kidney disease.
What does creatinine level mean?
Creatinine is a waste product produced by muscles. Normal levels are 0.7-1.3 mg/dL for men and 0.6-1.1 mg/dL for women. Higher creatinine suggests reduced kidney function because the kidneys are not filtering it efficiently. However, muscular individuals naturally have higher creatinine levels.
Should I be concerned if my GFR is low?
A single low GFR reading does not necessarily indicate kidney disease, dehydration, certain medications, and recent high-protein meals can temporarily affect results. If your GFR is below 60, your doctor will likely repeat the test in 3 months. Persistent low GFR warrants further evaluation.
Why does race affect the GFR calculation?
The race adjustment in the MDRD formula accounts for the observation that African Americans tend to have higher average muscle mass, which produces more creatinine. Some newer formulas (CKD-EPI 2021) have removed the race variable. Discuss the most appropriate formula with your healthcare provider.
This calculator is an educational estimate, not a medical test result and not a diagnosis. A diagnosis of chronic kidney disease can only be made by a nephrologist or other qualified physician, based on repeated laboratory tests over at least 3 months, urine studies and your full clinical picture. A single eGFR number can be misleading: laboratory variation, dehydration, recent high-protein meals, certain medications and creatine supplements all shift creatinine, and muscle mass strongly affects it, so very muscular people read falsely low eGFR and frail or elderly people read falsely high. Never start, stop or change any medication, diet or treatment based on this number alone. If your result is below 60, or you have diabetes, high blood pressure or a family history of kidney disease, take your actual lab report to a doctor.