The CKD-EPI eGFR calculator estimates glomerular filtration rate — the standard measure of kidney function. eGFR is used for CKD staging, drug dosing adjustments, and monitoring disease progression.
Calculate eGFR (CKD-EPI)
How to Use the GFR Calculator
This GFR calculator uses the CKD-EPI 2009 equation, the standard for eGFR estimation in most clinical laboratories. It calculates estimated glomerular filtration rate from serum creatinine, age, and sex.
Finding Your Serum Creatinine
Serum creatinine is measured in routine blood tests (metabolic panel, renal function panel). It is reported in mg/dL (US) or µmol/L (international). This calculator uses mg/dL — to convert from µmol/L, divide by 88.4.
CKD Staging by eGFR
G1 (≥90 mL/min): Normal or high — kidney damage present with normal function. G2 (60–89): Mildly decreased. G3a (45–59): Mild-to-moderate. G3b (30–44): Moderate-to-severe. G4 (15–29): Severely decreased — preparation for renal replacement therapy. G5 (<15): Kidney failure — dialysis or transplant typically required.
FAQ
Is this GFR calculator free?
Yes, completely free with no signup required.
What is eGFR and why is it important?
eGFR (estimated Glomerular Filtration Rate) measures how well your kidneys filter waste from blood. It is expressed in mL/min/1.73m². Normal eGFR is 90 or higher. Consistently low eGFR indicates chronic kidney disease (CKD) and determines the appropriate stage and treatment approach.
What is the CKD-EPI equation?
CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) is the most accurate eGFR equation for most adults with kidney disease. It uses serum creatinine, age, sex, and race. In 2021, the race variable was removed from the standard equation; many labs now use race-free CKD-EPI 2021.
What are the CKD stages?
CKD is staged by eGFR: G1 (≥90, normal/high); G2 (60-89, mildly decreased); G3a (45-59, mild-moderate decrease); G3b (30-44, moderate-severe); G4 (15-29, severely decreased); G5 (<15, kidney failure/dialysis required).
Does a single low eGFR mean I have CKD?
Not necessarily. CKD is defined by persistent kidney damage or decreased function for more than 3 months. A single low eGFR measurement should be confirmed with repeat testing. Dehydration, illness, and certain medications can temporarily lower eGFR without indicating permanent kidney disease.