eGFR (CKD-EPI 2021) Calculator
The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation is the current standard for estimating glomerular filtration rate (eGFR) in adults. Updated from the 2009 version, it removes the race variable and uses only serum creatinine, age, and sex. The result is expressed as mL/min/1.73m2, normalized to body surface area, allowing comparison across individuals. The equation uses a two-slope spline with kappa (0.7 for female, 0.9 for male) and alpha (-0.241 for female, -0.302 for male). This calculator is for educational and reference purposes only; clinical decisions require professional assessment.
CKD-EPI 2021 formula
eGFR = 142 x min(SCr/kappa, 1)^alpha x max(SCr/kappa, 1)^(-1.200) x 0.9938^Age x 1.012 (if female)
Female: kappa = 0.7, alpha = -0.241
Male: kappa = 0.9, alpha = -0.302
SCr is serum creatinine in mg/dL. min() and max() select the smaller or larger of the two operands. The equation is from the 2021 NKF-ASN Task Force update.
CKD staging by eGFR
- G1: eGFR 90+ mL/min/1.73m2 (normal or high; CKD only if markers present).
- G2: eGFR 60-89 (mildly decreased).
- G3a: eGFR 45-59 (mildly to moderately decreased).
- G3b: eGFR 30-44 (moderately to severely decreased).
- G4: eGFR 15-29 (severely decreased).
- G5: eGFR below 15 (kidney failure).
Frequently asked questions
What is the CKD-EPI 2021 equation?
CKD-EPI 2021 is the current recommended equation for estimating glomerular filtration rate (eGFR) from serum creatinine, age, and sex. It was updated in 2021 to remove the race variable that was present in the 2009 version, following guidance from NKF and ASN.
How does eGFR differ from creatinine clearance?
eGFR is normalized to 1.73 m2 body surface area and estimates the actual GFR in mL/min/1.73m2, making it comparable across patients of different sizes. Creatinine clearance (Cockcroft-Gault) is not BSA-normalized and is preferred for drug dosing.
What eGFR value defines chronic kidney disease?
CKD is defined as eGFR below 60 mL/min/1.73m2 for more than 3 months, or presence of kidney damage markers (proteinuria, imaging abnormalities) regardless of eGFR. CKD staging: G1 (90+), G2 (60-89), G3a (45-59), G3b (30-44), G4 (15-29), G5 (below 15).
Why was race removed from the CKD-EPI equation in 2021?
The 2009 equation included a Black race coefficient based on historical data, but this practice was found to perpetuate health inequities by systematically overestimating GFR in Black patients, potentially delaying referrals and transplant eligibility. The 2021 equation performs similarly without the race term.
How accurate is eGFR from creatinine alone?
eGFR from creatinine is a good screening tool but can be affected by muscle mass, diet, and certain medications. Cystatin C-based equations may be more accurate in some populations. For confirmatory staging, eGFR from cystatin C or a combined creatinine-cystatin C equation is preferred.
Official sources
- NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease: National Kidney Foundation GFR Calculator.
- NIDDK, NIH: CKD Tests and Diagnosis.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.