GFR Calculator
Estimate the glomerular filtration rate (eGFR) using creatinine and demographic data.
Tip: The creatinine value varies by laboratory — always use the correct unit (mg/dL or μmol/L) and your laboratory's reference range.
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About this digital tool
The GFR calculator estimates the glomerular filtration rate (eGFR), that is how well the kidneys filter the blood, from the creatinine level in the blood, age and gender. You can enter creatinine in mg/dL or μmol/L; the result is given in mL/min/1.73 m² and is linked to a stage of kidney function, from Stage 1 to Stage 5.
The calculation uses the CKD-EPI 2021 equation without the race factor. Values above 90 are considered normal if there are no other signs of damage, while a value below 60 that persists for over three months may indicate chronic kidney disease. The result is for information only and is not a diagnosis. Interpretation depends on other tests and clinical history, so it should always be done by a nephrologist or family doctor.
How to use
- Enter the creatinine value (mg/dL or μmol/L)
- Enter your age
- Choose your gender
- Enter your weight (for some formulas)
- See the eGFR and the stage of kidney function
Frequently asked questions
What is a normal GFR?
GFR >90 mL/min/1.73m² is considered normal. 60–89: slightly reduced. 30–59: moderately reduced (CKD stage 3). 15–29: severely reduced (stage 4). <15: kidney failure (stage 5, dialysis needed).
What affects GFR?
Age (falls naturally ~1 mL/min/year after 40), diabetes, hypertension, nephrotoxic drugs, dehydration, a very high-protein diet, and autoimmune diseases.
How often should I check it?
If you are healthy: every 1-2 years after age 40. If you have diabetes or hypertension: every 6–12 months. If GFR <60: every 3–6 months as medically advised.
What formula does the GFR calculator use?
It uses the CKD-EPI 2021 creatinine equation, which takes creatinine, age and gender into account. It does not use weight.
Can I use GFR to decide on treatment?
No. It is only an informational estimate. Diagnosis and treatment are decided by the doctor based on repeated tests and the clinical picture.