Estimate your kidney function using the CKD-EPI 2021 creatinine equation (race-free). Recommended by the National Kidney Foundation and KDIGO 2024 guidelines.
eGFR (estimated glomerular filtration rate) is a measure of how well your kidneys are filtering waste from your blood. It is calculated from a blood test that measures your serum creatinine level, combined with your age and sex. The result is expressed in mL/min/1.73m2, which represents the volume of blood filtered per minute, adjusted for body surface area. A normal eGFR is 90 or above. Below 60 for three or more months indicates chronic kidney disease.
This calculator uses the 2021 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation, which was published in the New England Journal of Medicine by Inker et al. The key update in 2021 was the removal of race as a variable in the calculation. The previous 2009 equation included a race coefficient that overestimated kidney function in Black patients and contributed to health disparities. The 2021 equation uses only three inputs: serum creatinine, age, and sex. It is endorsed by the National Kidney Foundation (NKF), the American Society of Nephrology (ASN), and the KDIGO 2024 clinical practice guidelines as the recommended first-line method for estimating GFR in adults.
G1 (eGFR 90+): Normal or high kidney function. Not CKD unless other markers of kidney damage are present. G2 (eGFR 60-89): Mildly decreased. May be age-appropriate in older adults. G3a (eGFR 45-59): Mildly to moderately decreased. CKD present. G3b (eGFR 30-44): Moderately to severely decreased. Nephrology referral recommended. G4 (eGFR 15-29): Severely decreased. Preparation for possible dialysis or transplant. G5 (eGFR below 15): Kidney failure. Dialysis or transplant typically needed.
Creatinine is a waste product produced by your muscles during normal activity. Healthy kidneys filter creatinine out of the blood and excrete it in urine. When kidney function declines, creatinine builds up in the blood. A higher creatinine level generally means lower kidney function. Normal creatinine ranges are roughly 0.74-1.35 mg/dL for adult males and 0.59-1.04 mg/dL for adult females, though these can vary by lab. Creatinine levels are also affected by muscle mass, diet (especially high-protein diets), and certain medications, which is why eGFR (which adjusts for age and sex) is a better indicator of kidney function than creatinine alone.
The CKD-EPI 2021 equation is designed for adults aged 18 and older with stable kidney function. It may be less accurate in people with very high or very low muscle mass (such as bodybuilders or amputees), acute kidney injury, pregnancy, or extreme diets. For more precise results, especially when eGFR is close to a treatment decision point, your doctor may order a cystatin C blood test and use the combined creatinine-cystatin C equation, which is more accurate than either marker alone.