eGFR Calculator

CKD-EPI 2021, without the race coefficient.

Calculate estimated glomerular filtration rate using the 2021 race-free CKD-EPI creatinine equation, with CKD staging.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Sex

Age

years

Serum creatinine

mg/dL

A single low value is not chronic kidney disease, that requires abnormalities persisting over three months. Creatinine also depends on muscle mass, so this misleads at extremes of build.

eGFR (mL/min/1.73m²)

G2, mildly reduced

EquationCKD-EPI 2021

Serum creatinine1 mg/dL

κ (sex constant)0.9

Race coefficientnot used

The 2021 refit removed the race coefficient earlier versions applied, which had reported higher function for Black patients and delayed referrals.

CKD stage by eGFR

Category	eGFR (mL/min/1.73m²)
G5, kidney failure	Below 15
G4, severely reduced	15 – 30
G3b, moderately reduced	30 – 45
G3a, mildly to moderately reduced	45 – 60
G2, mildly reducedYou	60 – 90
G1, normal or high	90 and above

How the eGFR Calculator works

eGFR estimates how much blood the kidneys filter per minute and is the basis for staging chronic kidney disease. The 2021 CKD-EPI refit removed the race coefficient that earlier versions applied, which had systematically reported higher function for Black patients and delayed referrals.

Also known as: estimated GFR calculator · CKD-EPI equation · kidney function calculator · egfr calculator · egfr estimator · egfr formula

Estimating filtration rate

Glomerular filtration rate is the volume of plasma filtered by the kidneys per minute, and it is the standard measure of kidney function. Measuring it directly requires infusing a marker substance, which is impractical in routine care.

Estimating equations use serum creatinine along with age and sex as proxies for creatinine production, which depends largely on muscle mass.

The result is reported normalised to a body surface area of 1.73 square metres, which allows comparison between people of different sizes and means the reported figure is not the individual's actual filtration rate.

Which equation, and the race coefficient

CKD-EPI, published in 2009, replaced the older MDRD equation and performs better at higher filtration rates, where MDRD systematically underestimated.

Both originally included a coefficient that produced a higher estimate for Black patients. In 2021 a joint task force of the National Kidney Foundation and American Society of Nephrology recommended removing it, and a race-free CKD-EPI equation was published and has been widely adopted.

The rationale for removal was that race is a social rather than biological category and that the coefficient delayed diagnosis and transplant referral for Black patients. UK laboratories have made the same change. Anyone comparing a current result against an older one should know that the equation changed.

The stages of chronic kidney disease

Stage 1 is an eGFR of 90 or above with evidence of kidney damage. Stage 2 is 60 to 89 with damage. Stage 3a is 45 to 59, 3b is 30 to 44, stage 4 is 15 to 29, and stage 5 is below 15.

Staging requires the reduction to be persistent, over at least three months, which is why a single low result is not a diagnosis of chronic kidney disease.

Albuminuria is staged alongside eGFR, because the combination predicts outcomes considerably better than eGFR alone. A patient with a moderately reduced eGFR and no albuminuria has a different prognosis from one with the same eGFR and heavy proteinuria.

Where the estimate misleads

Muscle mass drives creatinine production, so unusually muscular people have higher creatinine and a falsely low estimated GFR. Bodybuilders and some athletes are affected.

The reverse applies in low muscle mass: elderly, frail, malnourished or amputee patients can have a normal creatinine with substantially reduced kidney function.

Cystatin C is an alternative marker less dependent on muscle mass, and equations using it, or using both markers, are recommended where the creatinine-based estimate is thought to be unreliable. It is more expensive and less widely available.

Reading a result

A single reduced eGFR needs repeating before it means anything. Dehydration, recent heavy exercise, a high protein meal and several medications can all lower it temporarily.

A stable mildly reduced eGFR in an older adult is common and frequently does not progress. The trend over years matters more than any single value, and a falling trend is what prompts investigation.

This calculator implements a published equation. It does not know the clinical context, the albuminuria status, the trend, or anything else. Any result that concerns you is a conversation with the doctor who ordered the test, and that conversation will use considerably more information than two numbers.

Where to go next

The eGFR question rarely arrives on its own. These are the ones that usually come with it:

Creatinine Clearance Calculator — Cockcroft-Gault, the standard for renal drug dosing.
Body Surface Area Calculator — BSA by Du Bois, Mosteller, Haycock and Boyd.
Mean Arterial Pressure Calculator — MAP from systolic and diastolic, with perfusion thresholds.
BMI Calculator — Body mass index with category and healthy weight range.

Sources

Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.

Frequently asked questions

Why was the race coefficient removed?

Because race is a social category, not a biological variable, and applying a multiplier to it raised reported eGFR for Black patients, delaying specialist referral and transplant listing. A National Kidney Foundation and ASN task force recommended the race-free 2021 refit, now the standard.

What are the CKD stages?

G1: 90+ with evidence of kidney damage. G2: 60-89. G3a: 45-59. G3b: 30-44. G4: 15-29. G5: under 15, kidney failure. Stages G1 and G2 require additional evidence of damage, such as albuminuria, a normal eGFR alone is not CKD.

Does one low eGFR mean kidney disease?

No. Chronic kidney disease requires abnormalities persisting over three months. A single low value can reflect dehydration, recent high protein intake, some medications, or laboratory variation. Repeat testing is what establishes a trend.

Is eGFR accurate in unusual body types?

Less so at extremes. Creatinine comes from muscle, so eGFR overestimates function in people with very low muscle mass and underestimates it in very muscular ones. Cystatin C-based equations are recommended when the creatinine estimate is likely to mislead.