What eGFR measures
The glomerular filtration rate describes how much blood your kidneys clear of waste each minute, scaled to a standard body surface area of 1.73 m². Because measuring it directly is impractical, clinicians estimate it (eGFR) from a blood marker called creatinine together with your age and sex.
This calculator uses the 2021 CKD-EPI equation, the current standard in which the older race coefficient was removed in favour of a single, more equitable estimate.
Reading the CKD stage
The result maps your eGFR onto a chronic kidney disease stage from G1 to G5. The bar chart shows where your value falls relative to the key cut-offs of 90, 60, 30 and 15, which mark the boundaries between stages.
A higher eGFR is better. Values of 90 or above are normal, 60 to 89 are mildly reduced, and progressively lower numbers indicate more advanced loss of function down to kidney failure at G5.
What can affect the estimate
Several factors can move a single creatinine-based reading:
- Muscle mass — very muscular or very frail people can be misestimated.
- A high-protein meal or creatine supplements before the blood draw.
- Acute illness or dehydration at the time of the test.
- A single value is a snapshot; trends over time matter more.
Health disclaimer
This estimate is for general information only and is not a diagnosis. Kidney function is interpreted alongside urine tests, blood pressure, symptoms and history. Always discuss your results with a clinician before drawing any conclusions or changing treatment.
Formula
eGFR = 142·min(Scr/k,1)^a·max(Scr/k,1)^(−1.200)·0.9938^age·(1.012 if female); k = 0.7 (F)/0.9 (M); a = −0.241 (F)/−0.302 (M)Frequently asked questions
- Why race-free?
- The 2021 CKD-EPI equation removed the previous race coefficient to provide a single, more equitable estimate using only creatinine, age and sex.