eGFR Calculator (CKD-EPI 2021)
Estimated glomerular filtration rate (eGFR) gauges how well the kidneys filter blood. This calculator uses the 2021 CKD-EPI creatinine equation, the race-free formula endorsed by the National Kidney Foundation and the American Society of Nephrology. Enter standardized serum creatinine in mg/dL, age in years and sex, and it returns eGFR in mL/min/1.73 m2. eGFR helps stage chronic kidney disease, guide drug dosing and track kidney function over time. This is an educational estimate, not a diagnosis: a single value must be interpreted by a clinician with repeat testing and albuminuria.
2021 CKD-EPI creatinine formula
eGFR = 142 * min(Scr/k, 1)^a * max(Scr/k, 1)^-1.200 * 0.9938^Age * S
Female: k = 0.7, a = -0.241, S = 1.012
Male: k = 0.9, a = -0.302, S = 1.000
Scr = serum creatinine in mg/dL; Age in years
Result in mL/min/1.73 m2
The min/max terms apply different creatinine exponents below and above the sex-specific threshold k. The race coefficient present in older versions has been removed in this 2021 race-free equation.
How eGFR is interpreted
- G1: eGFR 90 or higher (normal or high), only CKD if kidney damage present.
- G2: 60 to 89, mildly decreased.
- G3a: 45 to 59; G3b: 30 to 44, moderately decreased.
- G4: 15 to 29, severely decreased.
- G5: below 15, kidney failure.
eGFR: frequently asked questions
Which eGFR equation does this calculator use?
It uses the 2021 CKD-EPI creatinine equation, the race-free formula recommended by the National Kidney Foundation and the American Society of Nephrology. It estimates GFR in mL/min/1.73 m2 from standardized serum creatinine, age and sex, without a race coefficient.
What units does the creatinine input use?
Enter standardized serum creatinine in mg/dL. If your lab reports in micromoles per liter (umol/L), divide by 88.4 to convert to mg/dL before entering. The equation requires an IDMS-standardized creatinine value.
What is a normal eGFR?
An eGFR of 90 mL/min/1.73 m2 or higher with no kidney damage is generally considered normal. Values are interpreted alongside markers like albuminuria. An eGFR below 60 for three or more months indicates chronic kidney disease, and below 15 indicates kidney failure.
Is this a diagnosis?
No. eGFR is an estimate, not a measured value, and a single result does not diagnose kidney disease. Results must be interpreted by a clinician alongside the full clinical picture, repeat testing and albuminuria. This tool is for education only.
Why was the race coefficient removed?
In 2021 a joint National Kidney Foundation and American Society of Nephrology task force recommended removing race from eGFR equations to promote equitable, accurate estimation. The 2021 CKD-EPI creatinine equation used here is the resulting race-free formula.
Official sources
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Estimating GFR resources.
- National Kidney Foundation: eGFR and CKD staging guidance.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.