A worked example
A 50-year-old male with a serum creatinine of 1.0 mg/dL has an estimated GFR of about 92 mL/min/1.73m² — Stage G1, normal kidney function.
Frequently asked questions
Why does this not ask for race?
The 2021 update specifically removed race as a variable — the earlier 2009 equation's race coefficient was found to overestimate kidney function in Black patients, which could delay needed care. The race-free version is now the recommended standard from the National Kidney Foundation and American Society of Nephrology.
What do the CKD stages mean?
G1-G2 (eGFR 60+) generally reflect normal-to-mildly-reduced function. G3a through G5 reflect progressively more significant kidney function decline, with G5 representing kidney failure. Staging also factors in albuminuria (protein in urine) clinically, which this calculator doesn't capture.
Can I rely on this number alone?
No — eGFR is a screening estimate that can be misleading in pregnancy, acute kidney injury, unusual muscle mass, or amputees, and a single value doesn't replace trend monitoring over time. Always discuss results with a healthcare professional.
This calculator provides estimates for general informational purposes only and is not a diagnosis or medical advice. Uses the 2021 CKD-EPI creatinine equation (Inker et al., NEJM 2021). Always consult a healthcare professional about your results.