🧪 GFR Calculator
Your kidneys filter about 180 litres of blood a day, and the eGFR number summarizes how well they do it from a single creatinine blood test plus your age and gender. Doctors stage chronic kidney disease directly from this figure.
This calculator uses the CKD-EPI 2021 equation — the current clinical standard, with no race factor. It is a screening estimate: only a doctor with your full labs can diagnose anything.
How to use this calculator
Enter your creatinine result, age and gender to estimate your kidney filtration rate.
- Enter your Creatinine in mg/dL from your blood test.
- Enter your Age.
- Select your Gender.
- Read the headline eGFR and the kidney stage label.
Frequently asked questions
What formula does this use?
The CKD-EPI 2021 equation, the current clinical standard with no race factor. It combines creatinine, age and gender: a 50-year-old man with creatinine 1.0 gets an eGFR near 92.
What do the stage labels mean?
G1 is normal at 90 and above, G2 mildly decreased at 60 to 89, G3a and G3b cover 30 to 59, G4 severely decreased at 15 to 29, and G5 kidney failure below 15. Staging also needs other tests, not eGFR alone.
My eGFR is 89. Should I worry?
A single mildly low reading with no other signs often just needs rechecking. eGFR naturally drifts down with age, and creatinine rises with muscle mass, so doctors interpret it alongside urine tests and history.
Can I improve my eGFR?
You cannot meaningfully raise the number itself, but controlling blood pressure, blood sugar, weight and salt protects the kidneys behind it. Never start or stop medication based on a calculator.