The estimated glomerular filtration rate (eGFR) reflects how well your kidneys filter waste from the bloodstream. Doctors rely on this measurement to assess kidney health, monitor chronic kidney disease, and adjust medication dosing. An eGFR below 60 mL/min/1.73m2 for several months often indicates impaired kidney function. Tracking changes over time helps clinicians determine whether lifestyle modifications or treatments are slowing disease progression.
Our calculator uses the CKD-EPI equation, published in 2009. The formula accounts for age, sex, serum creatinine level, and whether the patient identifies as Black. Creatinine is a waste product filtered by the kidneys. Higher creatinine levels typically correspond to lower filtration rates. The CKD-EPI formula is more accurate than older methods, especially when eGFR exceeds 60 mL/min/1.73m2. Mathematically, it is expressed as:
Where is serum creatinine, and depend on sex, and represents sex and race adjustments.
Begin by entering your age in years and your latest serum creatinine value in milligrams per deciliter. Choose your sex and whether you identify as Black. Race is included because earlier clinical studies found that Black patients tend to have higher average muscle mass, which affects baseline creatinine levels. Once you click “Calculate,” the script runs the CKD-EPI formula and presents your eGFR in milliliters per minute per 1.73 square meters of body surface area.
Healthy adults generally have eGFR values above 90. A reading between 60 and 89 can be normal for older adults but may signal early kidney damage in younger individuals. An eGFR below 60 suggests reduced kidney function, while a value under 15 indicates kidney failure. Always consult a healthcare professional to interpret your numbers, especially if you have other medical conditions. A single eGFR reading does not provide a full diagnosis—trends over time matter most.
Estimating eGFR from serum creatinine has inherent limitations. Creatinine generation varies with muscle mass, diet, and certain medications. Severe illness or abrupt dehydration can cause temporary fluctuations. This calculator is designed for adult patients; formulas for children differ. Additionally, some institutions have moved away from race-based adjustments. Discuss your results with your healthcare provider to understand how lab values fit into your personal health plan.
To support kidney function, stay hydrated, control blood pressure, manage blood sugar, and avoid excessive use of nephrotoxic medications such as nonsteroidal anti-inflammatory drugs. Following a diet low in sodium and saturated fats can help, as can regular exercise. Smoking cessation is also critical. If you have chronic kidney disease, your doctor may recommend limiting protein or consulting a renal dietitian for personalized guidance.
Consider a 55-year-old Black woman with a serum creatinine level of 1.0 mg/dL. For females, and . Plugging these values into the CKD-EPI equation yields an eGFR around 90 mL/min/1.73m2, within the normal range. Rechecking her values annually helps track any decline over time.
Kidney disease often progresses silently until advanced stages. Annual lab tests allow early detection and intervention, which can delay or prevent complications. People with diabetes, hypertension, or a family history of kidney disease are at higher risk and should monitor eGFR more closely. If your eGFR remains consistently low, your physician may order additional tests, such as urinary albumin or imaging studies, to pinpoint underlying causes.
If your eGFR is significantly below normal or drops rapidly, contact your healthcare provider promptly. Symptoms like swelling in the legs, persistent fatigue, or changes in urination patterns can signal declining kidney health. Early referral to a nephrologist—a kidney specialist—may slow progression and help manage related complications.
Compute creatinine clearance using the Cockcroft-Gault equation to evaluate kidney function.
Estimate 10-year coronary heart disease risk using the classic Framingham scoring model.
Estimate your insulin resistance using fasting glucose and insulin levels with the HOMA-IR formula.