eGFR from serum creatinine (mg/dL or µmol/L), age and sex by the race-free CKD-EPI 2021 equation, with optional cystatin C and the KDIGO G1–G5 stage.
For a man aged 50 with creatinine 1.00 mg/dL, the 2021 CKD-EPI equation gives an eGFR of 92 mL/min/1.73 m². That is KDIGO category G1: normal or high.
| GFR category | eGFR | A1 (ACR < 30 mg/g) | A2 (30–300) | A3 (> 300) |
|---|---|---|---|---|
| G1 (you) | ≥ 90 | Low | Moderate | High |
| G2 | 60–89 | Low | Moderate | High |
| G3a | 45–59 | Moderate | High | Very high |
| G3b | 30–44 | High | Very high | Very high |
| G4 | 15–29 | Very high | Very high | Very high |
| G5 | < 15 | Very high | Very high | Very high |
The ratio is 1 or more, so the min term equals 1 and the max term uses −1.200.
KDIGO 2024 asks for eGFR to be reported as a whole number in mL/min/1.73 m².
Creatinine eGFR reported as 92 → G1: normal or high. Bands: G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15.
Estimated glomerular filtration rate (eGFR) is the volume of blood plasma the kidneys filter each minute, scaled to a body surface area of 1.73 m². It is calculated from serum creatinine, age and sex with the 2021 CKD-EPI equation, which dropped the race coefficient of the 2009 version; the National Kidney Foundation and the American Society of Nephrology recommend it for adults in the US. With a cystatin C result the 2021 creatinine–cystatin C equation is also computed, and KDIGO 2024 grades the kidneys on that combined value when it is available.
Clinicians use eGFR to stage chronic kidney disease and to adjust drug doses. A 50-year-old man with a creatinine of 1.0 mg/dL (88 µmol/L) has an eGFR of 92, category G1. An eGFR below 60 for more than 3 months is chronic kidney disease, category G3a or worse.
The equations assume creatinine is stable. They read wrong in acute kidney injury, pregnancy, very high or low muscle mass, and after a meat-heavy meal or creatine supplements.
Checked against: Python 3.8 decimal: 142 × (1.0/0.9)^−1.200 × 0.9938^50 = 91.691 (NKF 2021 CKD-EPI creatinine equation); 1.0 × 88.4 = 88.40 µmol/L
Checked against: Python 3.8 decimal: 142 × (0.8/0.7)^−1.200 × 0.9938^60 × 1.012 = 84.298
Checked against: Python 3.8 decimal: 177 / 88.4 = 2.00226 mg/dL; 142 × (2.00226/0.9)^−1.200 × 0.9938^70 = 35.195
Checked against: Python 3.8 decimal: eGFRcr = 142 × (0.6/0.7)^−0.241 × 0.9938^45 × 1.012 = 112.735; eGFRcr-cys = 135 × (0.6/0.7)^−0.219 × (0.9/0.8)^−0.778 × 0.9961^45 × 0.963 = 102.910; eGFRcys = 133 × (0.9/0.8)^−1.328 × 0.996^45 × 0.932 = 88.513
90 mL/min/1.73 m² or higher is KDIGO category G1, normal or high, and 60 to 89 is G2, mildly decreased. Neither counts as chronic kidney disease unless there is also kidney damage, such as albumin in the urine, lasting at least 3 months. The equation lowers eGFR by 0.62 % for each year of age, so the same creatinine of 1.0 mg/dL gives a man 92 at age 50 and 81 at age 70.
An eGFR below 60 mL/min/1.73 m² that lasts more than 3 months meets the KDIGO 2024 definition of chronic kidney disease on its own. KDIGO grades it G3a (45–59), G3b (30–44), G4 (15–29) and G5, kidney failure (below 15). A single low reading is not a diagnosis, because acute illness, dehydration or a recent large meat meal can lower eGFR temporarily; KDIGO asks for repeat testing to confirm.
The 2009 CKD-EPI equation multiplied eGFR by 1.159 for Black patients, a coefficient based on race as a social category. A joint National Kidney Foundation and American Society of Nephrology task force recommended in 2021 that US labs switch to the refitted 2021 equation, which uses creatinine, age and sex only. KDIGO 2024 practice point 1.2.4.2 says race should not be used to compute eGFR.
When creatinine is likely to mislead. KDIGO 2024 Table 8 lists eating disorders, bodybuilding, above-knee amputation, spinal cord injury, vegetarian or high-protein diets and creatine supplements, among others. KDIGO recommends that when cystatin C is available the GFR category be taken from the combined creatinine–cystatin C equation, which is closer to measured GFR than either marker alone. A large gap between eGFRcr and eGFRcys is itself a signal that one of them is off.
Divide by 88.4, the factor in the KDIGO 2024 conversion table; it is 10,000 divided by the molar mass of creatinine, 113.12 g/mol. A result of 88 µmol/L is 1.00 mg/dL and 150 µmol/L is 1.70 mg/dL. KDIGO asks labs to report creatinine to the nearest whole number in µmol/L and to two decimals in mg/dL.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 8 worked examples whose answers come from independent sources; for example, “Man, 50 years, creatinine 1.0 mg/dL” is checked against Python 3.8 decimal: 142 × (1.0/0.9)^−1.200 × 0.9938^50 = 91.691 (NKF 2021 CKD-EPI creatinine equation); 1.0 × 88.4 = 88.40 µmol/L.
Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–1749; National Kidney Foundation — CKD-EPI creatinine equation (2021); National Kidney Foundation — CKD-EPI creatinine–cystatin C equation (2021); National Kidney Foundation — CKD-EPI cystatin C equation (2012); KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 2024;105(4S):S117–S314; Delgado C et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force. Am J Kidney Dis 2022;79:268–288.
For information only, not medical advice. These formulas describe populations, not you; talk to a clinician before acting on a result.
8 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
Blood pressure category (AHA/ACC) for a systolic/diastolic reading, from normal to stage 2 and severe hypertension, with pulse pressure and MAP.
Glucose from mg/dL to mmol/L and back, and HbA1c to estimated average glucose (eAG) and IFCC mmol/mol, with ADA categories.
Dose by weight from a mg/kg rate and body weight, capped at the single and daily maximum, with the liquid volume in mL for a given strength.
Body surface area (BSA) in m² from height and weight by the Mosteller, DuBois and Haycock formulas, with the spread between them.
Allow optional Google Analytics to measure page visits? Calculators work either way. Privacy and choices
Optional analytics: off.