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eGFR calculator (CKD-EPI 2021)

Free

Calculate estimated glomerular filtration rate (eGFR) using the CKD-EPI 2021 equation — the current standard for CKD staging reported by laboratories. Includes CKD stage, interpretation and clinical guidance. For drug dosing, use the Cockcroft-Gault CrCl Calculator instead.

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eGFR and CKD staging: what the numbers mean

eGFR (estimated glomerular filtration rate) measures how well your kidneys filter waste from the blood, expressed in mL/min/1.73m². It's the standard measure laboratories use to report kidney function and stage chronic kidney disease (CKD).

CKD-EPI 2021: why race was removed

The original CKD-EPI 2009 equation included a race coefficient that increased eGFR estimates for Black patients, based on the assumption of higher average muscle mass. This led to systematically delayed CKD diagnosis and transplant referral in Black patients. The 2021 revision removed this race variable entirely. The 2021 equation is now recommended by NIDDK, KDIGO and most major nephrology bodies.

eGFR vs CrCl for drug dosing

eGFR is used for CKD staging and clinical monitoring. For drug dosing, use Cockcroft-Gault CrCl — because that's the formula used to develop renal dosing guidelines. The values can differ significantly, especially in elderly patients. See our Creatinine Clearance Calculator and Renal Dose Adjustment Calculator.

CKD staging

G1 (eGFR ≥90): normal or high. G2 (60-89): mildly decreased. G3a (45-59): mild-moderate decrease. G3b (30-44): moderate-severe decrease. G4 (15-29): severe decrease. G5 (below 15): kidney failure. CKD staging also incorporates albuminuria — an eGFR alone doesn't fully stage CKD without urine protein data.

Frequently asked questions

What is a normal eGFR?

An eGFR of 90 or above (G1) indicates normal or high kidney function. 60-89 (G2) is mildly decreased but may be normal for older adults. Below 60 for more than 3 months indicates CKD. The threshold for dialysis consideration is generally below 15 (G5), though timing depends on symptoms and clinical context.

Why can't I use eGFR for drug dosing?

Renal dosing guidelines for most drugs were developed using Cockcroft-Gault CrCl values, not eGFR. The 2 equations use different methods and give different results, particularly in elderly, obese or very lean patients. Using eGFR for dosing can lead to errors. Always use Cockcroft-Gault CrCl for drug dosing decisions.

What is the difference between CKD-EPI 2021 and 2009?

The 2021 equation removed the race coefficient that was present in the 2009 version. The 2009 equation added approximately 16% to eGFR estimates for Black patients, which led to delayed CKD diagnosis and transplant referral in this population. The 2021 race-free equation is now recommended by NIDDK, KDIGO and most international nephrology bodies.