GFR Calculator

Written byOleh Soloninupdated 25 September 2026

Serum creatinine

Creatinine units

Age, years

Sex

Weight, kg

Only needed for Cockcroft-Gault.

Result

eGFR, CKD-EPI 2021, ml/min/1.73 m²

92.6

GFR category (KDIGO)G1 — normal or high
eGFR, CKD-EPI 2009, ml/min/1.73 m²88.6
Creatinine clearance, Cockcroft–Gault, ml/min97.2
Creatinine, mg/dl1.018
Creatinine, µmol/l90
What matters
A single reading is not a diagnosis: a CKD stage needs two measurements at least three months apart.

This result is informational only and is not professional advice.

One lab value, two different equations

Works out estimated GFR with the CKD-EPI 2021 equation and creatinine clearance with Cockcroft-Gault, gives the CKD stage, and converts creatinine between units.

Creatinine on its own says little: the same figure means very different kidney function in a young man and an elderly woman. That is why laboratories convert it into an estimated glomerular filtration rate adjusted for age and sex.

The current equation is CKD-EPI in its 2021 revision, which dropped the race coefficient. Cockcroft-Gault estimates something else — creatinine clearance — and needs body weight; it still appears in drug labelling, so both figures are shown side by side.

How to use

Enter the creatinine from your blood test and choose the unit printed on the report: µmol/l or mg/dl.
Enter age and sex — the CKD-EPI equations need both. Weight is used only for Cockcroft-Gault clearance.
Read the CKD-EPI 2021 eGFR and its KDIGO category, and the 2009 figure if your lab report uses the older equation.

GFR categories G1 to G5

KDIGO sorts GFR into six categories. A category is not a diagnosis: G1 and G2 count as chronic kidney disease only with other signs of kidney damage, and any reduction must last at least three months.

KDIGO 2012 categories as published by the National Kidney Foundation.
Category	GFR, ml/min/1.73 m²	Term
G1	90 or more	Normal or high
G2	60–89	Mildly decreased
G3a	45–59	Mildly to moderately decreased
G3b	30–44	Moderately to severely decreased
G4	15–29	Severely decreased
G5	Under 15	Kidney failure

What this calculator shows

eGFR by CKD-EPI 2021 in ml/min/1.73 m², with the CKD stage
eGFR by CKD-EPI 2009, to compare with lab reports that still use it
Creatinine clearance by Cockcroft-Gault in ml/min
The same creatinine in µmol/l and in mg/dl

What to keep in mind

The equation assumes a stable creatinine in adults from 18 years; it does not apply in acute kidney injury or in children.
This is reference arithmetic, not a diagnosis. A CKD diagnosis needs the changes shown to last at least three months: the clinician uses earlier and repeat results, a urine test and other clinical data, and does not always have to wait another three months.

Where the numbers come from

Checked against CKD-EPI 2021 (Inker et al., NEJM, 2021), CKD-EPI 2009, the Cockcroft–Gault equation (1976), KDIGO 2012 GFR categories.

FAQs

How does eGFR differ from creatinine clearance?

eGFR is normalised to a body surface area of 1.73 m² and is what CKD staging uses. Cockcroft-Gault clearance is not normalised and depends on weight; it survives in drug labelling.

Why does my lab report a different eGFR?

The lab may still use CKD-EPI 2009 or MDRD. Compare with the CKD-EPI 2009 line in the result: for a 45-year-old man with creatinine at 90 µmol/l it reads 88.6 against 92.6 by the 2021 equation.

What eGFR does a creatinine of 100 µmol/l give?

For a 45-year-old man, 81.6 ml/min/1.73 m², category G2; for a woman of the same age, 61.1, also G2. At 120 µmol/l the man reads 65.5 and the woman 49.1 — category G3a.

Why was the race coefficient removed?

Because race is not a biological marker of kidney function, and the old coefficient systematically overestimated eGFR in some patients and delayed their treatment. The 2021 revision works without it.

How do I convert creatinine from µmol/l to mg/dl?

Divide by 88.4. A value of 90 µmol/l is about 1.02 mg/dl.

Is an eGFR below 60 automatically kidney disease?

Not necessarily. CKD is diagnosed when the reduction persists for at least three months, or when other markers of kidney damage are present. A single result needs repeating.

Worked example

A routine result for a middle-aged man

Input: Creatinine 90 µmol/l, male, 45 years, 75 kg

Output: eGFR 92.6 — stage G1, clearance 97.2 ml/min

Note: The same creatinine in a woman of 70 gives 59.3, which is stage G3a. Age and sex matter as much as the lab value itself.

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