Estimate glomerular filtration rate and CKD stage using CKD-EPI and MDRD.
The GFR (glomerular filtration rate) measures how well the kidneys filter waste from the blood. eGFR is estimated from serum creatinine, age and sex. The CKD-EPI 2021 equation is the current clinical standard; it is race-free (the earlier 2009 version had a race coefficient that has been removed). MDRD is an older formula included for reference; it underestimates GFR in people with mild kidney impairment.
CKD-EPI 2021
eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^(−1.2) × 0.9938^Age × Sf
MDRD 4-variable
eGFR = 175 × Scr^(−1.154) × Age^(−0.203) × [0.742 if female]
This calculator estimates kidney function for informational and educational purposes. eGFR estimates from creatinine alone have limitations and should always be interpreted in the clinical context by a qualified healthcare provider. Do not make treatment decisions based solely on this estimate.
A GFR ≥ 60 mL/min/1.73 m² is generally considered normal for adults (CKD stages G1–G2). Note that GFR naturally declines with age — approximately 1 mL/min/1.73 m² per year after age 30.
The 2009 CKD-EPI equation included a racial coefficient that produced higher eGFR estimates for Black patients, delaying referrals to nephrology. The 2021 race-free version was developed to remove this bias and is now the recommended standard in the US, UK and elsewhere.
MDRD was developed in a population with moderate to severe kidney disease and systematically underestimates GFR above 60. CKD-EPI was developed from a broader population and performs better across the full range. When both are above 60, MDRD is less reliable.
No. CKD-EPI and MDRD are validated for adults ≥ 18 years. Paediatric kidney function is estimated with the Schwartz equation, which uses height instead of age.