Why was race removed from the equation?

Because it was never a biological variable. The 2009 CKD-EPI equation multiplied the estimate by about 1.16 for anyone recorded as Black, which systematically reported better kidney function and delayed referrals and transplant listing. The NKF-ASN task force reviewed it and recommended the 2021 race-free equation, which US laboratories have now largely adopted.

What is a normal GFR?

Around 120 mL/min/1.73m² in a healthy young adult, falling by roughly 1 mL a year from about thirty. An eGFR in the eighties is ordinary ageing at sixty; the same figure in a twenty-year-old is worth investigating. That is why the equation includes age at all.

What do the CKD stages mean?

G1 is 90 or above, G2 runs from 60 up to that line, G3a is 45 to 59, G3b is 30 to 44, G4 is 15 to 29 and G5 is below 15. Stages 1 and 2 only count as chronic kidney disease when there is other evidence of damage, typically albumin in the urine — a reduced eGFR alone in that range is not a diagnosis.

Why is my eGFR different at another laboratory?

Creatinine assays vary, and eGFR is sensitive to small differences: 0.1 mg/dL of creatinine moves the estimate by several units. Muscle mass, a recent high-protein meal and some medicines shift creatinine without any change in kidney function, which is why cystatin C is used as a check where the creatinine result and the clinical picture disagree.

GFR Calculator

With serum creatinine 1 mg/dL, age 60 years, gfr comes to 86.2 mL/min/1.73m² — estimated gfr. It is reached in 4 steps, the last of which is 142 * 1 * 0.8812335 * 0.6885564 * (1), and each one is printed on the page with its numbers filled in. The formula is the one published by Delgado C, Baweja M, et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force. Am J Kidney Dis. 2022;79(2):268–288., not an approximation fitted to it.

Estimated glomerular filtration rate by the 2021 CKD-EPI equation — the race-free one — with the CKD stage it falls in.

Formula and sources checked 27 August 2026 · How we check

Serum creatinine 1 mg/dL, Age 60 years, Sex Male

86.2 mL/min/1.73m²

Estimated GFR for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.

It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.

Serum creatininemg/dLFrom a blood test. In µmol/L, divide by 88.4 first.AgeyearsSex

Estimated GFR

86.2 mL/min/1.73m²

Estimated GFR: 142 * 1 * 0.8812335 * 0.6885564 * (1)86.163 mL/min/1.73m²
CKD stage, 1 to 5: 2
Share of a young adult’s filtration: 86.162621 / 120 * 10071.802 %
Creatinine in µmol/L: 1 * 88.488.4 µmol/L

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Worked example

A creatinine of 1.0 mg/dL in a 60-year-old man estimates a GFR of 86.2 — stage G2, which is a mild reduction and on its own is not kidney disease. The same result in a 60-year-old woman estimates 64.5, because the equation uses a lower κ for women rather than because their kidneys differ.

How to work it out yourself

1.Take the creatinine from a laboratory report. If it is in µmol/L — the usual unit outside the United States — divide by 88.4 to get mg/dL.
2.Read the stage as a band rather than a number. An eGFR of 59 and one of 61 sit in different stages and are the same kidney.
3.A single result means little. The definition of chronic kidney disease requires the abnormality to persist for at least three months, which is why the first low result leads to a repeat test rather than a diagnosis.

The formula

Estimated GFR142 * 1 * 0.8812335 * 0.6885564 * (1)
CKD stage, 1 to 5
Share of a young adult’s filtration86.162621 / 120 * 100
Creatinine in µmol/L1 * 88.4

Source: Delgado C, Baweja M, et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force. Am J Kidney Dis. 2022;79(2):268–288., NIDDK — estimating glomerular filtration rate

Questions people actually ask

Why was race removed from the equation?: Because it was never a biological variable. The 2009 CKD-EPI equation multiplied the estimate by about 1.16 for anyone recorded as Black, which systematically reported better kidney function and delayed referrals and transplant listing. The NKF-ASN task force reviewed it and recommended the 2021 race-free equation, which US laboratories have now largely adopted.
What is a normal GFR?: Around 120 mL/min/1.73m² in a healthy young adult, falling by roughly 1 mL a year from about thirty. An eGFR in the eighties is ordinary ageing at sixty; the same figure in a twenty-year-old is worth investigating. That is why the equation includes age at all.
What do the CKD stages mean?: G1 is 90 or above, G2 runs from 60 up to that line, G3a is 45 to 59, G3b is 30 to 44, G4 is 15 to 29 and G5 is below 15. Stages 1 and 2 only count as chronic kidney disease when there is other evidence of damage, typically albumin in the urine — a reduced eGFR alone in that range is not a diagnosis.
Why is my eGFR different at another laboratory?: Creatinine assays vary, and eGFR is sensitive to small differences: 0.1 mg/dL of creatinine moves the estimate by several units. Muscle mass, a recent high-protein meal and some medicines shift creatinine without any change in kidney function, which is why cystatin C is used as a check where the creatinine result and the clinical picture disagree.

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