Glomerular Filtration Rate (eGFR) Calculator

Calculate your estimated glomerular filtration rate (eGFR) with the race-free CKD-EPI 2021 equation using serum creatinine, age and sex. The result is an estimate and does not replace medical evaluation.

Enter your most recent serum creatinine result.

years

The CKD-EPI 2021 equation is used for adults aged 18 and older.

The equation uses different coefficients for females and males.

The calculator starts with example data: 0.9 mg/dL creatinine, age 50 and male. Replace these values with your own lab results.

You might be interested in:

P/F Ratio Calculator Mean Arterial Pressure (MAP)

What is estimated glomerular filtration rate?

Glomerular filtration rate (GFR) is an estimate of how much blood the kidneys filter through the glomeruli each minute. It is one of the most widely used indicators of kidney function and is usually expressed in milliliters per minute adjusted to a body surface area of 1.73 m².

When GFR is estimated from laboratory results and personal data, it is called estimated glomerular filtration rate (eGFR). You may also see it described as estimated kidney filtration or estimated renal function.

Information needed to calculate eGFR

This calculator uses serum creatinine, age and the sex used by the 2021 CKD-EPI equation. Creatinine should come from a laboratory test, and the selected unit must match the unit on your result.

  • Serum creatinine: enter it in mg/dL or µmol/L. The calculator converts µmol/L to mg/dL before applying the equation.
  • Age: the selected equation is intended for adults aged 18 and older.
  • Sex: the equation uses one set of coefficients for females and another for males.

CKD-EPI 2021 equation

The 2021 CKD-EPI creatinine equation estimates GFR without a race coefficient. Serum creatinine should be standardized and expressed in mg/dL before applying the equation.

eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 (if female)
  • Scr: standardized serum creatinine in mg/dL.
  • κ: 0.7 for females and 0.9 for males.
  • α: −0.241 for females and −0.302 for males.
  • min and max: select the minimum or maximum value between Scr/κ and 1.

How should eGFR be interpreted?

Categories G1 through G5 provide an orientation about the estimated filtration level. A single result does not confirm chronic kidney disease: interpretation depends on whether the result persists, other markers such as albuminuria and the clinical context.

  • G1 (≥90): normal or high; by itself, it does not indicate chronic kidney disease.
  • G2 (60–89): mildly decreased; it should be interpreted together with other markers of kidney damage.
  • G3a (45–59) and G3b (30–44): mildly to moderately or moderately to severely decreased.
  • G4 (15–29) and G5 (<15): severely decreased or kidney failure.

In general, chronic kidney disease is considered when an abnormality persists for at least three months or other signs of kidney damage are present. Do not use this classification to adjust medication or make treatment decisions on your own.

Calculator limitations

The CKD-EPI 2021 equation is intended to estimate GFR in adults and assumes that the creatinine result is reliable and kidney function is relatively stable. It may be less representative in situations such as acute kidney injury, pregnancy, extremes of muscle mass, amputation or conditions and diets that alter creatinine production.

eGFR is not a direct measurement of filtration and does not replace professional medical assessment. If you have an unexpected result, symptoms or known kidney disease, consult your healthcare team.

Sources and references

The equation and general information in this tool were checked against the following medical sources:

  1. National Kidney Foundation: eGFR calculator.
  2. National Kidney Foundation: CKD-EPI creatinine equation (2021).
  3. NIDDK: eGFR equations for adults.