🫘 GFR Calculator
Estimate glomerular filtration rate (eGFR) and CKD stage using the CKD-EPI 2021 race-free formula.
Your Details
Your Result
| Stage | GFR (mL/min/1.73m²) | Description |
|---|---|---|
| Stage 1 | ≥ 90 | Normal kidney function |
| Stage 2 | 60 – 89 | Mildly reduced |
| Stage 3a | 45 – 59 | Mild to moderate reduction |
| Stage 3b | 30 – 44 | Moderate to severe reduction |
| Stage 4 | 15 – 29 | Severely reduced |
| Stage 5 | < 15 | Kidney failure |
Medical disclaimer: This calculator is for educational purposes only and is not a diagnosis. eGFR results can be affected by muscle mass, diet, pregnancy, and other factors. Always discuss kidney function results with a qualified healthcare provider.
How the GFR Calculator Works
Glomerular filtration rate (GFR) estimates how well your kidneys filter waste from the blood. This calculator uses the 2021 CKD-EPI creatinine equation, a race-free formula recommended by the National Kidney Foundation and American Society of Nephrology.
Formula
Female, Scr > 0.7: GFR = 142 × (Scr/0.7)^−1.2 × 0.9938^age × 1.012
Male, Scr ≤ 0.9: GFR = 142 × (Scr/0.9)^−0.302 × 0.9938^age
Male, Scr > 0.9: GFR = 142 × (Scr/0.9)^−1.2 × 0.9938^age
Chronic Kidney Disease (CKD) Stages
CKD stages range from Stage 1 (normal or high function, but with other evidence of kidney damage) to Stage 5 (kidney failure, often requiring dialysis or transplant). A single low reading isn't a diagnosis — CKD is typically confirmed when reduced function persists for three months or more.
Frequently Asked Questions
What is a normal GFR?
A GFR of 90 or above is generally considered normal, though it naturally declines somewhat with age. A single low value does not necessarily indicate kidney disease.
Why was race removed from the GFR formula?
The 2021 CKD-EPI equation removed the race coefficient used in earlier versions, following recommendations from a national task force to create a more equitable formula that doesn't rely on self-reported race.
Can this calculator diagnose kidney disease?
No. It provides an estimate for educational purposes only. Diagnosis requires clinical evaluation by a healthcare provider, often including repeated testing over time.