eGFR Calculator (CKD-EPI 2021, Race-Free) — Estimate Kidney Function

Q: What is a good eGFR for my age?

An eGFR of 90 or above is generally considered normal, and 60–89 is common and often normal in older adults because filtration declines gradually with age. eGFR is not staged by age — the same value means the same level of measured function at any age — but a result of 75 in a 30-year-old may warrant more attention than the same value at 80. Persistently below 60 (for more than three months) is the threshold that defines reduced kidney function.

eGFR Calculator (CKD-EPI 2021)

Estimate your kidney function from a creatinine result. Uses the 2021 race-free CKD-EPI equation — the current US and European standard — with a toggle for the Japanese (JSN) equation.

eGFR (estimated glomerular filtration rate) measures how well your kidneys filter blood, in mL/min/1.73m². It's calculated from your serum creatinine, age and sex. An eGFR of 90+ is normal; below 60 for more than three months indicates reduced kidney function.

2021 CKD-EPI race-free equation Runs in your browser — nothing sent Medically reviewed

Does your eGFR vary for you?

A creatinine number isn't read the same way for everyone. Here's where sex, age and region actually change the result — and where they don't.

SexChanges the math

Sex is built into the equation. For the same creatinine, the formula applies different coefficients for women and men (and a small upward female adjustment), because creatinine partly reflects muscle mass. The calculator above handles this — switch the Sex field and the result updates.

AgeChanges the math

Age is a direct term in the equation — eGFR declines gradually with age for the same creatinine, reflecting normal age-related filtration decline. Note the value isn't staged by age: an eGFR of 70 means the same level of function at 30 as at 75, even if it's more expected at 75.

Region / ethnicityChanges the equation

The US & Europe use the race-free CKD-EPI 2021 equation. Japan uses the JSN equation, which can return a meaningfully different value for the same creatinine — toggle it above. China, Thailand and India use their own calibrated equations; if your lab reports one of these, your value may differ from the standard. Older equations applied a now-removed Black-race coefficient.

How eGFR is calculated

eGFR isn't measured directly — it's estimated from creatinine using a validated equation. Here's the exact formula behind the calculator, so you can see how the number is produced.

2021 CKD-EPI creatinine equation (race-free)

eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^Age × 1.012 [if female]

Scr = serum creatinine (mg/dL) · κ = 0.7 (female) / 0.9 (male) · α = −0.241 (female) / −0.302 (male)

The equation takes your creatinine, normalises it by sex (the κ and α terms), applies an age decay factor, and adds a small female adjustment. The output is standardised to a body surface area of 1.73m², which is why the units are mL/min/1.73m² rather than a raw filtration rate. The 2021 version is the one to use because it removed the race coefficient that older equations applied — the joint National Kidney Foundation and American Society of Nephrology task force recommended this in 2021 to make the estimate independent of race.

The Japanese (JSN) equation toggle uses a different model — eGFR = 194 × Scr^−1.094 × Age^−0.287 × 0.739 [if female] (Matsuo et al., 2009) — calibrated to a Japanese population. This is why the same creatinine can produce a different eGFR depending on which equation your lab applies. Always check which equation underlies the number on your report.

What your eGFR result means

eGFR maps to a kidney function stage (G1–G5). Higher is better. The stage below is based on the value alone — a full clinical diagnosis also needs the chronicity and albuminuria context noted underneath.

Stage	eGFR (mL/min/1.73m²)	What it indicates
G1	90 or above	Normal or high filtration. Healthy kidney function (unless other damage markers are present).
G2	60–89	Mildly decreased. Common and often normal with age — only flagged as CKD if damage markers (e.g. albuminuria) are also present.
G3a	45–59	Mild-to-moderate reduction. Warrants follow-up and monitoring with a clinician.
G3b	30–44	Moderate-to-severe reduction. Needs clinical assessment and management.
G4	15–29	Severely decreased. Specialist nephrology care typically required.
G5	Below 15	Kidney failure. Dialysis or transplant may be needed.

Stage

eGFR (mL/min/1.73m²)

What it indicates

90 or above

Normal or high filtration. Healthy kidney function (unless other damage markers are present).

60–89

Mildly decreased. Common and often normal with age — only flagged as CKD if damage markers (e.g. albuminuria) are also present.

G3a

45–59

Mild-to-moderate reduction. Warrants follow-up and monitoring with a clinician.

G3b

30–44

Moderate-to-severe reduction. Needs clinical assessment and management.

15–29

Severely decreased. Specialist nephrology care typically required.

Below 15

Kidney failure. Dialysis or transplant may be needed.

eGFR alone is not a diagnosis

Chronic kidney disease is defined as reduced eGFR or markers of kidney damage (such as albuminuria) that persist for more than three months. A single low reading can be caused by dehydration, recent high protein intake, some medications, or high muscle mass. One value below 60 means repeat the test and discuss it with a clinician — it does not by itself confirm kidney disease.

Frequently asked questions

How do I calculate my eGFR?

eGFR is estimated from your serum creatinine, age and sex using a validated equation — most commonly the 2021 CKD-EPI creatinine equation. You don't compute it by hand: enter your creatinine (mg/dL or µmol/L), age and sex into the calculator above and it applies the equation. The result is reported as mL/min/1.73m², standardised to an average adult body surface area.

What is a good eGFR for my age?

An eGFR of 90 or above is generally normal, and 60–89 is common and often normal in older adults because filtration declines gradually with age. eGFR isn't staged by age — the same value means the same level of function at any age — but a result of 75 in a 30-year-old may warrant more attention than the same value at 80. Persistently below 60 for more than three months is the threshold that defines reduced kidney function.

What is the new eGFR formula?

The current standard is the 2021 CKD-EPI creatinine equation, which removed the race coefficient older equations applied to Black patients. It estimates eGFR from creatinine, age and sex only, and was introduced by a joint National Kidney Foundation and American Society of Nephrology task force to make the estimate independent of race. Some countries use population-calibrated equations instead — Japan uses the JSN equation derived from a Japanese population.

Does eGFR vary by ethnicity or country?

Yes. The equation used to convert creatinine into eGFR differs by region. The US and Europe now use the race-free 2021 CKD-EPI equation. Japan uses the JSN equation (Matsuo 2009), calibrated to a Japanese population, which can return a different value for the same creatinine. China, Thailand and India have their own modified equations. Because the equation differs, the same creatinine can produce different eGFR numbers — always check which equation your report is based on.

Is a low eGFR result the same as kidney disease?

Not on its own. A single low eGFR is a snapshot and can be affected by dehydration, recent high protein intake, certain medications, or muscle mass. Chronic kidney disease is defined as reduced eGFR (below 60) or markers of kidney damage such as albuminuria that persist for more than three months. A single reading below 60 means repeat the test and discuss it with a clinician — it does not by itself confirm a diagnosis.

Note: This calculator is for informational purposes and does not replace medical advice. eGFR estimates are less accurate at the extremes of body size and muscle mass, in pregnancy, and in acute illness. Always interpret your result alongside the reference range and equation printed on your own report, and discuss any concern with a clinician who has your full history.