GFR Calculator
Estimate glomerular filtration rate (eGFR) from age, sex, and serum creatinine.
Assumptions used in this calculation
- Formula: Uses the 2021 CKD-EPI creatinine equation (race-free version), the current standard in US clinical guidelines.effective 2021 · CKD-EPI 2021 (National Kidney Foundation / ASN Task Force)
About this calculator
A serum creatinine number from a blood test doesn't mean much on its own, kidney function assessment requires converting that value, along with age and sex, into an estimated glomerular filtration rate (eGFR), a measure of how well the kidneys are filtering blood. This calculator applies the 2021 CKD-EPI creatinine equation, the current US clinical standard (and race-free, unlike its predecessor), which combines your serum creatinine level against sex-specific reference constants (κ and α) with an age-decay factor and a female adjustment, to produce an eGFR value in mL/min/1.73m². The formula involves piecewise exponents that aren't practical to compute by hand. The result places you into a general kidney function range, from normal to severely reduced, but this is an estimate for informational purposes only. A real kidney function assessment needs a doctor's interpretation of this and other clinical values together, not a single calculated number viewed in isolation.
Worked example
Male, 50 years old, creatinine 1.0 mg/dL
Result: eGFR ≈ 91.7 mL/min/1.73m² (Normal or high)
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