eGFR Calculator

Estimated glomerular filtration rate (eGFR) estimates how well your kidneys are filtering waste from your blood. It is reported in mL/min/1.73 m squared. A normal eGFR is 90 or above. The eGFR is calculated from serum creatinine, age, and sex using validated equations.

KDIGO staging: G1 = eGFR 90+ (normal or high); G2 = 60-89 (mildly decreased); G3a = 45-59 (mild to moderate decrease); G3b = 30-44 (moderate to severe decrease); G4 = 15-29 (severely decreased); G5 = below 15 (kidney failure). CKD is diagnosed when abnormalities persist for 3 or more months.

This calculator uses the 2021 CKD-EPI creatinine equation (race-free version), which is now recommended by the National Kidney Foundation and American Society of Nephrology. It was updated in 2021 to remove race as a variable, improving equitable care for Black patients.

Creatinine is a waste product from normal muscle metabolism. Healthy kidneys filter creatinine from the blood into the urine. When kidney function declines, creatinine accumulates in the blood. Serum creatinine is the most commonly measured marker of kidney function and is used to estimate GFR.

Chronic kidney disease (diabetes-related nephropathy is the most common cause), acute kidney injury, severe dehydration, heart failure, certain medications (NSAIDs, aminoglycosides), and obstructive uropathy. A single low eGFR reading may not indicate CKD; repeated measurements over months are required for diagnosis.