GFR Calculator

Calculate estimated GFR (eGFR) using the CKD-EPI 2021 race-free equation and interpret the result against CKD staging guidelines.

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Patient details

Estimated GFR
87
mL/min/1.73m²
CKD Stage G2 — Mildly decreased

eGFR 60–89 mL/min/1.73m². Mildly decreased function. CKD G2 only when other kidney damage markers present.

Clinical considerations
  • ·A single eGFR reading in this range does not confirm CKD without other kidney damage markers (e.g. proteinuria, haematuria, structural abnormality)
Monitoring:Annual creatinine/eGFR check if risk factors present (diabetes, hypertension). Otherwise routine as per GP.

Uses CKD-EPI 2021 creatinine equation (race-free). eGFR is an estimate based on serum creatinine, age, and sex. It can be affected by muscle mass, diet, and acute illness. This result is for educational reference only — clinical decisions require assessment by a healthcare professional with access to your full medical history.

Health — Kidney

GFR Calculator (eGFR)

Estimated glomerular filtration rate (eGFR) is the standard measure of kidney function in clinical practice. Calculated from serum creatinine, age, and sex, eGFR provides an estimate of how well the kidneys are filtering waste products from the blood. This calculator uses the CKD-EPI 2021 equation — the current gold-standard race-free formula recommended by the NHS and NICE.

CKD-EPI 2021: the race-free equation

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation superseded the 2009 version by removing the race coefficient, which had been criticised for potentially overestimating eGFR in Black patients and thereby delaying CKD diagnosis. The 2021 equation uses only serum creatinine, age, and sex, and has been adopted by NHS England and NICE as the standard formula.

eGFR naturally declines with age in healthy adults — approximately 1 mL/min/1.73m² per year after age 40. An eGFR of 60–89 in an older adult without other markers of kidney damage (e.g., proteinuria, haematuria, structural abnormality) may represent normal ageing rather than CKD. CKD staging requires confirmation over ≥3 months.

Frequently asked questions

What is the normal eGFR range?

An eGFR ≥60 mL/min/1.73m² is generally considered within the normal range, though values 60–89 indicate mildly decreased function. CKD is defined as eGFR <60 persisting for ≥3 months, or eGFR ≥60 with other markers of kidney damage. eGFR naturally declines with age.

 Why does sex affect eGFR?

The CKD-EPI equation incorporates a sex-specific factor because women have lower muscle mass on average than men of the same age, producing less creatinine. For the same serum creatinine value, a woman's eGFR is estimated higher than a man's because the lower baseline creatinine suggests better-than-average kidney function relative to her muscle mass.

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