GFR Calculator

Serum creatinine

Creatinine units

Age, years

Sex

Weight, kg

Only needed for Cockcroft-Gault.

Result

eGFR, ml/min/1.73 m²92.6
Stage by eGFRG1 — normal or high
Cockcroft-Gault clearance, ml/min97.2
Creatinine, mg/dl1.018
Creatinine, µmol/l90
What mattersA 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.

What this calculator shows

eGFR by CKD-EPI 2021 in ml/min/1.73 m², with the CKD stage
Creatinine clearance by Cockcroft-Gault for drug dosing
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 stage comes from a clinician using two results at least three months apart alongside a urine test.

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 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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Result

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