What is the difference between CKD-EPI and MDRD?

CKD-EPI is more accurate at higher GFR values and is the current recommended equation, while MDRD tends to underestimate normal kidney function. The 2021 CKD-EPI refit removed the race coefficient. This tool reports both for comparison.

Why is CKD-EPI 2021 race-free?

The 2021 refit dropped the Black-race adjustment after evidence that race is a social, not biological, variable and that the old coefficient could delay care. The tool uses the race-free CKD-EPI equation by default.

What do the G-stages mean?

KDIGO defines stages from G1 (normal, eGFR 90 or above) through G3a and G3b (moderate) to G5 (kidney failure, below 15). Staging guides monitoring frequency, referral, and drug dosing. The tool labels the CKD-EPI result with its stage.

When is eGFR unreliable?

eGFR assumes stable kidney function and average muscle mass. It is inaccurate in acute kidney injury, pregnancy, amputees, body-builders, very low muscle mass, and rapidly changing creatinine. In those cases a measured clearance or cystatin C may be needed.

Does it send my data anywhere?

No. The equations run entirely in your browser. Age, creatinine, and sex are never transmitted or stored on any server.

eGFR Calculator (CKD-EPI & MDRD)

Estimated glomerular filtration rate (eGFR) is the standard measure of kidney function used to stage chronic kidney disease and adjust drug doses. This tool computes eGFR with two validated creatinine-based equations and labels the result with its KDIGO stage.

How it works

The race-free CKD-EPI 2021 equation, with creatinine in mg/dL, is:

eGFR = 142 * min(Scr/K, 1)^a * max(Scr/K, 1)^-1.200 * 0.9938^age
       * 1.012 (if female)
  female: K = 0.7, a = -0.241
  male:   K = 0.9, a = -0.302

The legacy IDMS-traceable MDRD (175) equation is shown for comparison:

eGFR = 175 * Scr^-1.154 * age^-0.203 * 0.742 (if female) * 1.212 (if Black)

If creatinine is entered in µmol/L it is converted to mg/dL by dividing by 88.42. The CKD-EPI result is mapped to a G-stage from G1 to G5.

Example

A 60-year-old man with a creatinine of 1.0 mg/dL has a CKD-EPI 2021 eGFR of about 89 mL/min/1.73m², stage G2 (mildly decreased).

Notes

eGFR assumes stable function and average muscle mass; it is unreliable in acute illness, pregnancy, and at extremes of body composition. CKD-EPI 2021 is the current recommendation, while MDRD is retained here only for cross-checking historical results. This is an educational estimate, not a diagnosis.