GFR Calculator

The CKD-EPI 2021 race-free equation, the current standard recommended by the National Kidney Foundation and the American Society of Nephrology. It estimates eGFR from serum creatinine, age, and sex only, with no race input. The result is rounded to the nearest whole number and reported in mL/min/1.73 m^2.

Earlier CKD-EPI equations applied a multiplier that raised estimated GFR for Black patients, which produced artificially higher numbers, delayed specialist referrals, and longer transplant waitlist times. The 2021 revision drops the race adjustment entirely. US labs and health systems adopted the updated equation starting in 2021 and 2022.

Healthy adults with no kidney risk factors typically have eGFR checked during routine bloodwork every 1 to 3 years. If you have diabetes, high blood pressure, or a known CKD stage, your doctor usually retests every 3 to 12 months depending on the stage and how stable your numbers are. This calculator is an estimate, so follow your doctor's testing schedule.

GFR declines gradually with age even in healthy kidneys, so the average drops by roughly 1 mL/min/1.73 m^2 per year after about age 40. Population mean eGFR is around 116 in your 20s, about 99 in your 40s, and about 85 in your 60s. This calculator classifies eGFR 90 or above as G1 (normal); an eGFR of 60 to 89 (G2) is only considered chronic kidney disease if there is added evidence of kidney damage, such as protein in urine.

Creatinine is a waste product of normal muscle metabolism that healthy kidneys continuously filter from your blood. A higher creatinine level generally means the kidneys are clearing less, but the raw number is heavily influenced by muscle mass, high meat intake, and some medications, which is why the CKD-EPI formula adjusts for sex and age to produce a more meaningful estimate. This calculator accepts creatinine values between 0.1 and 15 mg/dL.