eGFR Calculator

Estimated Glomerular Filtration Rate (eGFR) measures how efficiently your kidneys filter waste products and excess fluid from your bloodstream. Expressed in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73 m²), a normal eGFR in healthy young adults is typically 90 or higher. As kidneys age or experience damage, the filtration rate decreases. eGFR helps clinicians detect kidney impairment early, often before physical symptoms appear.

The 2021 CKD-EPI equation calculates eGFR using three inputs: your serum creatinine level (measured in mg/dL or µmol/L from a standard blood test), your age in years, and your biological sex at birth. Creatinine is a natural waste byproduct of muscle metabolism that healthy kidneys filter into urine. If kidney function drops, creatinine accumulates in the blood, resulting in a lower calculated eGFR score.

The international KDIGO guidelines define five stages of Chronic Kidney Disease based on persistent eGFR levels: Stage 1 (eGFR ≥90): Normal or high kidney function, but other markers of kidney damage (such as protein in urine) are present. Stage 2 (eGFR 60–89): Mildly decreased kidney function with persistent kidney damage. Stage 3a (eGFR 45–59): Mild-to-moderate loss of kidney function. Stage 3b (eGFR 30–44): Moderate-to-severe loss of kidney function. Stage 4 (eGFR 15–29): Severe reduction in kidney function; preparation for renal replacement therapy. Stage 5 (eGFR <15): Kidney failure (end-stage renal disease / ESRD), requiring dialysis or transplantation.

No. A single low eGFR is not sufficient for a diagnosis of Chronic Kidney Disease. Temporary dips in eGFR can be caused by dehydration, acute illness, strenuous physical workouts prior to blood draw, high dietary protein intake (especially cooked meat), or certain medications (e.g., NSAIDs, ACE inhibitors, antibiotics). Chronic Kidney Disease is diagnosed only when eGFR remains below 60 mL/min/1.73 m² (or kidney damage markers persist) for at least three consecutive months.

In 2021, the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) joint task force recommended replacing older equations with the new race-free 2021 CKD-EPI formula. Extensive clinical research demonstrated that incorporating race as a biological proxy was inaccurate, contributed to clinical disparities, and delayed timely diagnosis and nephrology referrals for diverse populations.

Comprehensive kidney health evaluation always includes: 1) Urine Albumin-to-Creatinine Ratio (uACR): Detects trace amounts of albumin (protein) leaking through damaged kidney filters, which often precedes drops in eGFR. 2) Cystatin C: An alternative blood biomarker produced by all nucleated cells, unaffected by muscle mass or diet. 3) Blood Urea Nitrogen (BUN) and Electrolytes: Evaluates overall metabolic and fluid balance. 4) Blood Pressure & HbA1c: Assesses diabetes and hypertension, the two leading root causes of kidney disease.

You can upload your complete blood and urine test reports into ZoctorAI's Free AI Report Analysis. ZoctorAI automatically extracts and cross-correlates your eGFR, serum creatinine, BUN, electrolytes, and uACR, providing plain-language summaries, clinical context, reference ranges, and trend charts through Vitality Track.