GFR Calculator
Enter a recent serum creatinine value with your age and sex to estimate glomerular filtration rate and see the corresponding chronic kidney disease stage.
eGFR (CKD-EPI 2009)
90 mL/min/1.73m²
eGFR (MDRD)
81 mL/min/1.73m²
CKD stage (CKD-EPI)
Stage 1 - Normal or high
Educational estimate only - always interpret kidney function with your healthcare provider alongside full lab results.
How to Use the GFR Calculator
- Get your serum creatinine value from a blood test result.
- Enter creatinine, age and sex, choosing mg/dL or µmol/L units.
- Read your estimated GFR in mL/min/1.73m² and the matched CKD stage.
Formulas Used
CKD-EPI (2009): eGFR = 141 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.209 × 0.993^age (×1.018 female)
MDRD: eGFR = 175 × Scr^−1.154 × age^−0.203 (×0.742 female)
Frequently Asked Questions
What is a normal GFR?
Above 90 mL/min/1.73m² is normal (stage 1). Values of 60-89 suggest mild reduction, and below 60 for three months or more indicates chronic kidney disease.
Why does the formula use 1.73 m²?
GFR is normalised to standard body surface area so results compare across people of different sizes; very small or large adults may need unnormalised values for dosing decisions.
Can muscle mass affect my eGFR?
Yes. Creatinine comes from muscle turnover, so very muscular people can look like they have lower kidney function, while low-muscle elders can mask real impairment.
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