How do I calculate eGFR from creatinine?

You need blood creatinine, age and sex. The calculator puts them into the CKD-EPI 2021 equation and returns eGFR in mL / min / 1.73 m² and a kidney function stage. Enter creatinine in µmol / L (if yours is mg / dL, multiply by 88.4).

What eGFR is considered normal?

In healthy adults eGFR is usually 90 or above (stage G1). Values of 60–89 (G2) without kidney-damage markers are also normal for many, especially with age. An eGFR below 60 persisting ≥3 months indicates chronic kidney disease.

What are CKD stages G1–G5?

A classification by eGFR: G1 (≥90) and G2 (60–89) are normal or mildly reduced, G3a/G3b (30–59) moderate, G4 (15–29) severe, G5 (<15) kidney failure. A doctor sets the stage using urine tests and the trend.

Why is cystatin C useful?

Cystatin C is a second kidney-function marker that doesn’t depend on muscle mass. The combined CKD-EPI equation (creatinine + cystatin C) is more accurate than creatinine alone — especially for athletes, older people and those with low muscle mass, where creatinine can mislead.

Does a low eGFR definitely mean kidney disease?

Not necessarily. A single low value can come from dehydration, high muscle mass, a meat-heavy meal or medication. Disease is indicated by a persistent drop ≥3 months and/or damage markers (protein in urine). A doctor makes the assessment.

eGFR calculator (glomerular filtration rate)

Q: Why is cystatin C useful?

Cystatin C is a second kidney-function marker that doesn’t depend on muscle mass. The combined CKD-EPI equation (creatinine + cystatin C) is more accurate than creatinine alone — especially for athletes, older people and those with low muscle mass, where creatinine can mislead.

Q: Does a low eGFR definitely mean kidney disease?

Not necessarily. A single low value can come from dehydration, high muscle mass, a meat-heavy meal or medication. Disease is indicated by a persistent drop ≥3 months and/or damage markers (protein in urine). A doctor makes the assessment.

eGFR (estimated glomerular filtration rate) shows how well your kidneys clean the blood. Enter creatinine from a blood chemistry panel, your age and sex — the calculator computes eGFR with the modern CKD-EPI 2021 equation and determines the kidney function stage. Know your cystatin C? Add it for an even more accurate estimate.

Calculate eGFR and your kidney function stage

Enter creatinine, age and sex — the result appears instantly.

eGFR and chronic kidney disease (CKD) stages

Classification by eGFR (KDIGO), mL / min / 1.73 m². A low eGFR alone isn’t a diagnosis: the CKD stage is set by a doctor using urine tests and repeat measurements.

eGFR, mL / min / 1.73 m²	Stage
90 and above	G1 — normal or high
60–89	G2 — mildly decreased
45–59	G3a — mild–moderate
30–44	G3b — moderate–severe
15–29	G4 — severely decreased
below 15	G5 — kidney failure

What eGFR is and why it’s calculated

eGFR is the volume of blood your kidneys filter per minute (normalised to a standard body surface of 1.73 m²). It’s the main measure of kidney function: measuring it directly is hard, so it’s estimated from blood creatinine adjusted for age and sex.

Creatinine is a muscle-breakdown product cleared by the kidneys. The worse they filter, the higher the creatinine and the lower the eGFR. So a high eGFR is good, and a low one is worth looking into.

How eGFR is calculated: CKD-EPI 2021

The calculator uses the CKD-EPI 2021 equation — the modern standard without a race coefficient (removed as invalid). It takes creatinine, age and sex. Creatinine is measured in µmol / L in many countries; if yours is in mg / dL, multiply by 88.4.

Entering cystatin C switches to the combined CKD-EPI equation (creatinine + cystatin C), which is more accurate — especially for people with atypical muscle mass, where creatinine alone can mislead.

Why one value isn’t a diagnosis

A low eGFR on a single test doesn’t mean kidney disease: creatinine is affected by dehydration, muscle mass, meat intake and medication. Chronic kidney disease is diagnosed when the drop persists ≥3 months and/or there are damage markers (protein in urine, ultrasound changes).

So eGFR is read over time and together with a urine test (albumin/creatinine), urea and kidney ultrasound. The calculator gives a guide, not a verdict.

Adults only

The CKD-EPI equation is designed for adults. In children eGFR is estimated with a different equation (Schwartz) that includes height, so a child’s result from this calculator is not valid.

Frequently asked questions

You need blood creatinine, age and sex. The calculator puts them into the CKD-EPI 2021 equation and returns eGFR in mL / min / 1.73 m² and a kidney function stage. Enter creatinine in µmol / L (if yours is mg / dL, multiply by 88.4).
In healthy adults eGFR is usually 90 or above (stage G1). Values of 60–89 (G2) without kidney-damage markers are also normal for many, especially with age. An eGFR below 60 persisting ≥3 months indicates chronic kidney disease.
A classification by eGFR: G1 (≥90) and G2 (60–89) are normal or mildly reduced, G3a/G3b (30–59) moderate, G4 (15–29) severe, G5 (<15) kidney failure. A doctor sets the stage using urine tests and the trend.
Cystatin C is a second kidney-function marker that doesn’t depend on muscle mass. The combined CKD-EPI equation (creatinine + cystatin C) is more accurate than creatinine alone — especially for athletes, older people and those with low muscle mass, where creatinine can mislead.
Not necessarily. A single low value can come from dehydration, high muscle mass, a meat-heavy meal or medication. Disease is indicated by a persistent drop ≥3 months and/or damage markers (protein in urine). A doctor makes the assessment.

eGFR is one value from a blood test

Upload the whole report — AI reads creatinine, urea and eGFR together, links them to other markers and explains what to do.

Decode my blood test

This calculator is for reference and information only and is not a diagnosis. The kidney disease stage is determined by a doctor from the eGFR trend, urine tests and ultrasound.