eGFR Calculator
Estimate kidney function (eGFR) from serum creatinine, age and sex with the 2021 CKD-EPI equation.
About the eGFR Calculator
Glomerular filtration rate measures how much blood the kidneys filter each minute. Labs estimate it from a creatinine blood test. The 2021 CKD-EPI equation, recommended by the US National Kidney Foundation and American Society of Nephrology, no longer includes race.
The formula
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 (if female)
- κ
- 0.7 (female), 0.9 (male)
- α
- −0.241 (female), −0.302 (male)
- Scr
- serum creatinine in mg/dL (µmol/L ÷ 88.42)
KDIGO GFR categories
| Category | eGFR | Description |
|---|---|---|
| G1 | 90+ | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | under 15 | Kidney failure |
Worked example
Example: eGFR (CKD-EPI 2021) = 86 mL/min/1.73 m²
- Inputs: Sex: Male; Age: 61 years; Creatinine unit: mg/dL; Serum creatinine: 1.
- Formula: eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 (if female)
- Result: eGFR (CKD-EPI 2021) = 86 mL/min/1.73 m²
- Creatinine in mg/dL: 1
Things to keep in mind
- This is an estimate for general information, not medical advice. Talk to a doctor or other qualified professional about your health.
- Not accurate for children, pregnancy, very high or low muscle mass, or rapidly changing kidney function.
Questions people ask
Why was race removed?
Race isn't a biological measure; the 2021 equation was refitted without it to avoid biased results.
Is a single low result CKD?
No. Diagnosis needs eGFR below 60 for at least 3 months or other evidence of kidney damage.