eGFR Calculator (CKD-EPI 2021)
What is eGFR Calculator (CKD-EPI 2021)
The eGFR calculator estimates your glomerular filtration rate, a measure of how well the kidneys filter blood. It uses the 2021 CKD-EPI creatinine equation, the race-free version now recommended in the United States and widely adopted elsewhere. From serum creatinine, age and sex it returns an eGFR in mL/min/1.73m² and maps it to the KDIGO category from G1 (normal) to G5 (kidney failure).
How to use
- Enter the age of the patient in years.
- Type the serum creatinine value and pick its unit, mg/dL or µmol/L.
- Select the sex used in the equation.
- Read the estimated GFR and its CKD stage in the result panel.
When to use it
Got a creatinine result back and want to know what it means for kidney function? Enter a creatinine of 1.4 mg/dL for a 65-year-old man and you get an eGFR near 52 mL/min/1.73m², which falls in stage G3a. It is handy for tracking chronic kidney disease over time, checking whether a drug dose needs adjusting, or simply reading a lab report without the raw number sitting there unexplained.
Frequently asked questions
Which equation does this calculator use?
It uses the CKD-EPI 2021 creatinine equation. This is the refit that removed the race coefficient, endorsed by the NKF-ASN Task Force, and it reports eGFR indexed to a body surface area of 1.73m².
Why is there no race input?
The 2021 equation was specifically designed to drop race. Earlier CKD-EPI and MDRD formulas applied a separate multiplier for Black patients, which is no longer recommended, so this tool needs only creatinine, age and sex.
When is eGFR unreliable?
Creatinine-based eGFR assumes a stable, steady-state creatinine and average muscle mass. It can mislead in acute kidney injury, in people with very high or very low muscle mass, in pregnancy and in children, where other formulas or a cystatin C measurement are preferred.
Can I share this tool with my inputs pre-filled?
Yes. The URL updates automatically as you type. Copy it from the address bar or use the Copy link button, and anyone who opens the link will see your exact inputs ready to go.
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