eGFR Calculator (CKD-EPI 2021)
Estimate your glomerular filtration rate from serum creatinine, age and sex using the 2021 race-free CKD-EPI equation — the method recommended by the National Kidney Foundation. Enter your values to get an eGFR in mL/min/1.73 m² and the matching CKD stage.
The CKD-EPI 2021 equation
eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 [if female], with Scr in mg/dL, κ = 0.7 (female) or 0.9 (male), and α = −0.241 (female) or −0.302 (male). The result is standardised to a body surface area of 1.73 m². Source: National Kidney Foundation, CKD-EPI Creatinine Equation (2021).
Frequently asked questions
How is eGFR calculated?
This calculator uses the 2021 CKD-EPI creatinine equation: eGFR = 142 × min(Scr/κ, 1)ᵅ × max(Scr/κ, 1)⁻¹·²⁰⁰ × 0.9938ᵃᵍᵉ × 1.012 (if female), where Scr is serum creatinine in mg/dL, κ is 0.7 for females and 0.9 for males, and α is −0.241 for females and −0.302 for males. For example, a 50-year-old man with a creatinine of 1.0 mg/dL has an eGFR of about 92 mL/min/1.73 m². A creatinine entered in µmol/L is divided by 88.4 before the equation is applied. The answer is expressed per 1.73 m² of body surface area, which is what makes it comparable between people of different size.
Why is the 2021 equation race-free?
Earlier CKD-EPI equations applied a separate coefficient for Black patients. The 2021 refit removed the race term so the same equation is used for everyone, using only creatinine, age and sex. The National Kidney Foundation and ASN recommend it as the standard for reporting eGFR.
What is a normal eGFR?
A normal eGFR in healthy young adults is roughly 90–120 mL/min/1.73 m², declining gradually with age. An eGFR of 60 or above with no other signs of kidney damage is generally considered normal; a value below 60 that persists for three months or more indicates chronic kidney disease. This calculator labels each result with its KDIGO G-stage, from G1 at 90 or above down to G5 below 15. Creatinine-based eGFR is least reliable at extremes of muscle mass, in pregnancy and when kidney function is changing quickly, so a single number is read alongside albuminuria and the clinical picture.
What are the CKD stages?
The CKD stages by eGFR are: G1 (normal) ≥ 90, G2 (mildly decreased) 60–89, G3a 45–59, G3b 30–44, G4 (severely decreased) 15–29, and G5 (kidney failure) below 15. Stages G1–G2 are only classed as CKD when other markers of kidney damage are present, and any stage requires the reduction to persist for at least three months. The G-stages describe filtration alone; KDIGO also stages albuminuria as A1, A2 or A3, and the two axes together set the risk category. This calculator reports the G-stage only, because it takes creatinine, age and sex and no urine result.
Should I use mg/dL or µmol/L for creatinine?
Use whichever your lab report shows — switch the unit in the calculator to match. Conventional (US) reports use mg/dL; most other countries use µmol/L. The two are the same measurement: µmol/L ÷ 88.4 = mg/dL.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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