eGFR calculator (CKD-EPI 2021)
This tool estimates kidney filtration from a blood creatinine result and shows the stage in the KDIGO classification.
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How to use it
- Enter sex, age, serum creatinine and creatinine unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^-1.200 × 0.9938^age × 1.012 if female, where κ = 0.7 (female) or 0.9 (male), α = -0.241 (female) or -0.302 (male), and Scr is in mg/dL (µmol/L ÷ 88.4).
Example
Inputs: Sex = Male, Age = 50 years, Serum creatinine = 1, Creatinine unit = mg/dL. Result: eGFR: 92 mL/min/1.73 m²; Stage (KDIGO): G1: normal or high; Creatinine in mg/dL: 1.
Limits and caveats
- It is for adults with stable creatinine and does not fit acute kidney injury or unusual muscle mass.
- Chronic kidney disease needs a reduction lasting 3 months or other signs of damage, not a single reading.
- An educational estimate that does not replace assessment by a doctor or pharmacist.
Questions about this tool
How does the 2021 equation differ from the older one?
The 2021 equation removed the race coefficient and refitted the constants. NKF and ASN in the United States recommend it.
How do I convert creatinine from µmol/L?
Divide by 88.4, so 88.4 µmol/L equals 1.0 mg/dL. The tool does this for you when you pick the unit.
Does a low eGFR mean kidney disease?
Not always. A value below 60 for 3 months or more points to chronic kidney disease, and a doctor confirms it with other tests.