Kidney eGFR Calculator (CKD-EPI 2021)

🧪 Kidney eGFR Calculator (CKD-EPI 2021)

Enter your bloodwork details to calculate your Kidney Function Index.

What eGFR means

eGFR (estimated glomerular filtration rate) estimates how many millilitres of blood your kidneys filter each minute, adjusted to a standard body size (mL/min/1.73 m²). It is calculated from the creatinine level in a blood test, together with age and sex.

This calculator uses the CKD-EPI 2021 creatinine equation, which is the version recommended in the United States since 2021 and does not use race. It is for adults aged 18 and over.

Units

Enter creatinine in mg/dL. If your report shows µmol/L, divide by 88.4 (for example 84 µmol/L ≈ 0.95 mg/dL).

GFR categories (KDIGO)

  • G1, 90 or more: normal or high.
  • G2, 60–89: mildly decreased. Common in older adults.
  • G3a, 45–59: mildly to moderately decreased.
  • G3b, 30–44: moderately to severely decreased.
  • G4, 15–29: severely decreased.
  • G5, below 15: kidney failure.

Chronic kidney disease (CKD) is diagnosed only when eGFR stays below 60 for at least 3 months, or when there are other signs of kidney damage such as albumin (protein) in the urine. One result is never enough on its own.

When eGFR can be misleading

  • Creatinine comes from muscle, so very muscular people may get a falsely low eGFR, and people with low muscle mass (frail, amputation, long illness) a falsely high one.
  • A big meat meal, creatine supplements, intense exercise or dehydration before the test can raise creatinine temporarily.
  • The equation is not valid during sudden kidney injury, pregnancy, or for children.

Your doctor may confirm a borderline result with a cystatin C test or a repeat creatinine.

Educational estimate only. Please discuss your result with your doctor.