Kidney function
eGFR calculator
Estimate your glomerular filtration rate from your creatinine, age, and sex using the race-free CKD-EPI 2021 equation, and see the corresponding kidney-function stage explained.
Enter your values above to see your result and what it means.
What is eGFR and what does it measure?
eGFR stands for estimated glomerular filtration rate — an estimate of how much blood your kidneys filter each minute, scaled to body size and reported in mL/min/1.73m². It is calculated from a blood creatinine level together with your age and sex, not measured directly. Because it is an estimate, it gives a useful overall picture of kidney function rather than an exact figure.
The CKD-EPI 2021 formula explained
This calculator uses the CKD-EPI 2021 creatinine equation, the current race-free formula recommended for estimating GFR in adults. It takes your creatinine, age, and sex and returns an eGFR value. Different equations and lab methods can produce slightly different numbers, so compare this estimate with the eGFR printed on your own report.
What is a normal eGFR range?
A higher eGFR generally indicates better filtering capacity, and many labs describe values at or above a certain threshold as within the expected range for healthy kidneys. Exact reference ranges and how they apply to you depend on the lab and your clinical context, so read this estimate alongside your report. The number is a screening signal, not a diagnosis.
Normal eGFR by age
eGFR tends to decline gradually with age as kidney function naturally decreases, so a value that is typical for an older adult may differ from a younger one. The CKD-EPI equation already builds age into the calculation, which is why the same creatinine gives different eGFR results at different ages. A modest age-related decline is common and is best interpreted by a clinician in context.
What does a low eGFR mean, and the CKD stages
Lower eGFR values are grouped into chronic kidney disease (CKD) stages, where smaller numbers indicate more reduced filtering. A single low estimate can be affected by hydration, recent meals, muscle mass, or certain medicines, so staging is based on repeated results over time, not one reading. This tool shows the stage your estimate falls into for information only — it does not diagnose kidney disease.
eGFR and creatinine: how they relate
Creatinine is the waste product the eGFR equation is built around: as kidney filtering falls, creatinine in the blood tends to rise, which lowers the estimated eGFR. That inverse relationship is why a high creatinine often accompanies a low eGFR. Entering your creatinine here lets the calculator turn that raw lab value into the more interpretable eGFR figure.
Frequently asked questions
What is a normal eGFR?
An eGFR of 90 or above is generally considered normal, and 60–89 is common and often normal too, especially with age, if there are no other signs of kidney damage. Below 60 for three months or more is one of the markers used to define chronic kidney disease.
Does one low eGFR mean I have kidney disease?
No. Chronic kidney disease requires a reduced eGFR or other damage markers that last at least three months. A single low result can be caused by dehydration, a recent illness, or certain medicines, so clinicians repeat the test and check urine before concluding anything.
Why does the calculator ask for sex but not race?
The 2021 CKD-EPI equation uses age, sex, and creatinine, and — unlike older versions — does not include a race coefficient. Sex is used because creatinine levels differ with typical muscle mass.
My creatinine is in µmol/L — can I use this?
This calculator expects creatinine in mg/dL. To convert, divide a µmol/L value by 88.4 (for example, 80 µmol/L ÷ 88.4 ≈ 0.9 mg/dL).