What Is GFR and Why It Matters
A plain explanation of glomerular filtration rate and what your number reveals about kidney function.
Last updated: 2026-09-24
Glomerular filtration rate (GFR) is the best single measure of how well the kidneys filter blood. It estimates how much blood the kidneys clear each minute.
How it is measured
GFR is usually estimated (eGFR) from a blood creatinine test plus age and sex — no separate procedure is required.
What the number means
A normal GFR is roughly 90 or above. A value below 60 persisting for three months generally indicates chronic kidney disease.
Frequently asked questions
What GFR indicates kidney failure?
Below 15, when dialysis or transplantation is usually discussed.