Renal & electrolytes

eGFR calculator

Kidney function from a single creatinine — with the CKD stage, the reference, and South African units first.

FreeNo sign-upWorks offlineNo patient data stored
Age
years
Sex
Serum creatinine
µmol/L
Reference: CKD-EPI 2021 race-free creatinine equation (Inker et al., NEJM). Adults only.Not validated for AKI or pregnancy.

How to read the result

Estimated GFR (mL/min/1.73 m²) falls into these published bands.

< 15CKD G5Kidney failure.
15 – 29CKD G4Severely decreased kidney function.
30 – 44CKD G3bModerately to severely decreased kidney function. Review renally cleared drug doses.
45 – 59CKD G3aMildly to moderately decreased kidney function.
60 – 89CKD G2Mildly decreased kidney function.
≥ 90CKD G1Normal or high kidney function.
Worked example

A 64-year-old woman with a serum creatinine of 124 µmol/L (1.4 mg/dL).

eGFR 42 mL/min/1.73 m² — CKD stage G3b

Moderately to severely decreased kidney function: renally cleared drug doses need review, and the stage anchors monitoring frequency and referral thresholds.

Who this is for

For clinicians checking chronic kidney function, staging CKD, or screening before nephrotoxic drugs and contrast. Takes creatinine in µmol/L as SA laboratories report it (mg/dL one tap away), and applies the race-free CKD-EPI 2021 equation now recommended by KDIGO.

How it works

What it calculates

Estimated glomerular filtration rate from serum creatinine, age, and sex using the CKD-EPI 2021 equation — the race-free revision now recommended by KDIGO — with the corresponding CKD stage (G1–G5).

When to use it

Assessing chronic kidney function, staging CKD, and screening before nephrotoxic drugs or contrast. It assumes a steady-state creatinine: it is not valid in acute kidney injury, pregnancy, or extremes of muscle mass.

eGFR or creatinine clearance?

eGFR is normalised to 1.73 m² and best for staging; many drug dosing references were validated against Cockcroft-Gault creatinine clearance — use the CrCl tool for those decisions.

Built on published evidence

  • CKD-EPI 2021 race-free creatinine equation (Inker et al., NEJM). Adults only

Codification last reviewed 2026-08-28, and checked against published reference values in automated tests on every release — see the full evidence ledger.

Questions clinicians ask

Which equation does this calculator use?

The CKD-EPI 2021 creatinine equation — the race-free revision (Inker et al., NEJM 2021) now recommended by KDIGO. Older CKD-EPI 2009 and MDRD estimates can differ slightly, which is expected.

Can I enter creatinine in µmol/L?

Yes — µmol/L is the default, matching South African laboratory reports, with mg/dL one tap away. The conversion (1 mg/dL = 88.4 µmol/L) is handled exactly.

When should I use creatinine clearance instead of eGFR?

eGFR is normalised to 1.73 m² and best for staging chronic disease. Many drug-dosing references were validated against Cockcroft-Gault creatinine clearance — use the CrCl tool for those decisions. Neither is valid in acute kidney injury, where creatinine is not at steady state.

Does it work offline and is patient data stored?

It works fully offline once loaded, and no patient data is stored or transmitted — values stay in your browser tab only.

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Information tool for healthcare professionals — not medical advice. Terms of use