MDRD eGFR Calculator
The Modification of Diet in Renal Disease (MDRD) Study equation estimates glomerular filtration rate from serum creatinine, age and sex. This calculator uses the IDMS-traceable 4-variable form (coefficient 175), for standardized creatinine assays, and returns eGFR in mL/min/1.73 m2. By default it does not apply a race factor, in line with the move to race-free estimation, with an optional toggle for the historical 1.212 multiplier. The newer 2021 CKD-EPI equation is now preferred for reporting; MDRD is provided for comparison and legacy results. This is an educational estimate, not a diagnosis.
4-variable MDRD formula
eGFR = 175 * Scr^-1.154 * Age^-0.203 * F * R
F = 0.742 if female, else 1
R = 1.212 if historical race factor applied, else 1
Scr in mg/dL; result in mL/min/1.73 m2
The coefficient 175 is the IDMS-traceable version for standardized creatinine. By default R is 1 (race-free). The 2021 CKD-EPI equation is preferred for new reporting.
CKD stage reference
- G1: 90 or higher; G2: 60 to 89.
- G3a: 45 to 59; G3b: 30 to 44.
- G4: 15 to 29; G5: below 15.
- MDRD is less accurate at higher GFR values.
- Prefer the 2021 CKD-EPI equation for new results.
MDRD eGFR: frequently asked questions
What is the MDRD equation?
The Modification of Diet in Renal Disease (MDRD) Study equation estimates glomerular filtration rate from serum creatinine, age and sex. This calculator uses the IDMS-traceable 4-variable form with the coefficient 175, designed for standardized creatinine assays.
Should I include the race factor?
Historically the MDRD equation multiplied the result by 1.212 for Black patients. Current guidance favors race-free estimation, and the 2021 CKD-EPI equation is preferred for new reporting. This calculator defaults to no race factor, with an optional toggle for the historical version.
What units does it use?
Serum creatinine is entered in mg/dL and age in years. The result is in mL/min/1.73 m2. If creatinine is reported in umol/L, divide by 88.4 to convert to mg/dL first.
How does MDRD differ from CKD-EPI?
Both estimate GFR from creatinine, but CKD-EPI (especially the 2021 race-free version) is more accurate at higher GFR values and is the currently recommended equation. MDRD is included here because many older results and references use it.
Is this a diagnosis?
No. eGFR is an estimate, not a measured value, and one result does not diagnose kidney disease. Interpretation belongs with a clinician. This calculator is for education only.
Official sources
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Estimating GFR resources.
- National Kidney Foundation: eGFR equations and CKD staging.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.