Formula or algorithm and variables.
eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^Age × 1.012 if femaleFor the 2021 race-free creatinine equation, κ is 0.7 and α −0.241 for the female coefficient set; κ is 0.9 and α −0.302 for the male set.
Equation, units, and population
eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^Age × 1.012 if female. For the 2021 race-free creatinine equation, κ is 0.7 and α −0.241 for the female coefficient set; κ is 0.9 and α −0.302 for the male set. This page names the equation rather than presenting an unexplained score. Check that every value uses the displayed unit and that you belong to the population for which the method is described. The calculation retains full precision internally and rounds only the visible result. A reproducible estimate should let another reader use the same inputs and reach the same arithmetic answer, while still recognizing that mathematical reproducibility does not prove medical suitability.
Worked example
For age 50, serum creatinine 1.0 mg/dL, and the female coefficient set, the 2021 CKD-EPI equation produces an estimate near 69 mL/min/1.73 m². Work through the example by writing the equation, substituting each labeled input, and preserving units at every step. The example demonstrates arithmetic only; it is not a recommended body measurement, intake, exercise level, laboratory value, or date. Replace every example input with the values from the situation being considered, and retain those inputs with any result you copy. Small differences can arise from rounding, equation versions, atomic-weight conventions, or date boundaries.
Interpreting the estimate
The result is an estimate normalized to 1.73 m² body surface area. One result does not establish chronic kidney disease, which requires clinical context and persistence or other evidence. Health calculations compress complex biology into a few inputs, so the result should be read as context rather than a verdict. Do not compare two people as though the higher or lower number is automatically better. Look for changes over time only when the method, units, and conditions are consistent. If a result conflicts with symptoms, a laboratory report, a clinician’s instructions, or a validated measurement, rely on the appropriate professional evidence rather than this calculator.
Validation and edge cases
Age must be 18–120 and serum creatinine 0.1–20 mg/dL. The equation version and coefficient set remain visible with the result. Blank, malformed, nonfinite, and out-of-domain inputs fail explicitly without producing NaN or infinity. The bounds prevent obviously implausible values from being mistaken for meaningful answers, but passing a range check does not make an input medically correct. Recheck dates, decimal separators, unit conversions, coefficient choices, and whether a laboratory value uses the expected assay and unit. Contact a qualified professional when a result could affect treatment, medication, pregnancy care, nutrition therapy, or exercise safety.
Limitations and responsible use
This exact equation is for adults 18 and older using standardized serum creatinine. Creatinine can be less reliable with unusual muscle mass, amputation, malnutrition, rapidly changing kidney function, pregnancy, or some medicines. An eGFR estimate is not a kidney-disease diagnosis. A clinician interprets trends, urine testing, symptoms, medicines, acute illness, and other evidence. FigureNest processes these inputs locally in the browser and does not send them to a calculation service. The page does not create a medical record, assess symptoms, or know personal history. Avoid using estimates to shame a body, pursue unsafe restriction, delay care, determine legal fitness, or replace contraception. Authoritative source links are provided so readers can check the equation version and current guidance before making a consequential decision.
Check assumptions and sources.
This exact equation is for adults 18 and older using standardized serum creatinine. Creatinine can be less reliable with unusual muscle mass, amputation, malnutrition, rapidly changing kidney function, pregnancy, or some medicines.
Common questions.
What does the eGFR Calculator estimate?
Estimate adult kidney filtration with the race-free 2021 CKD-EPI creatinine equation and explicit clinical limitations.
Which equation and units does it use?
eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^Age × 1.012 if female. For the 2021 race-free creatinine equation, κ is 0.7 and α −0.241 for the female coefficient set; κ is 0.9 and α −0.302 for the male set.
Is this medical advice or a diagnosis?
No. An eGFR estimate is not a kidney-disease diagnosis. A clinician interprets trends, urine testing, symptoms, medicines, acute illness, and other evidence.
Which limitations matter most?
This exact equation is for adults 18 and older using standardized serum creatinine. Creatinine can be less reliable with unusual muscle mass, amputation, malnutrition, rapidly changing kidney function, pregnancy, or some medicines.