Glomerular Filtration Rate (eGFR)
Calculate eGFR using CKD-EPI and MDRD equations. Enter creatinine, age, gender, and race to get eGFR, CKD stage (1-5), and clinical interpretation. Free kidney function calculator with comparison charts.
About This Calculator
The Glomerular Filtration Rate (eGFR) Calculator estimates how well your kidneys filter waste from your blood. eGFR is the primary screening test for chronic kidney disease (CKD) and is recommended for anyone with diabetes, high blood pressure, a family history of kidney disease, or age over 60. Early detection of reduced kidney function allows for lifestyle changes and treatments that can slow disease progression.
This calculator uses two validated medical formulas. The CKD-EPI (2009) equation is the current standard recommended by the National Kidney Foundation and is more accurate at higher GFR values. The MDRD (Modification of Diet in Renal Disease) equation is provided as a reference for comparison. Both formulas use serum creatinine, age, gender, and race to estimate GFR. The result is expressed in mL/min/1.73m², which is normalized to a standard body surface area.
Regional Notes
United States: The NKF recommends CKD-EPI as the standard equation. Most US labs report eGFR automatically with creatinine results. Some institutions are transitioning to race-free CKD-EPI (2021). Medicare covers annual eGFR testing for at-risk individuals.
United Kingdom: NICE guidelines recommend CKD-EPI for eGFR reporting. The NHS offers free kidney function testing through GP surgeries. The UK uses the same CKD staging system with eGFR categories G1 through G5.
India: eGFR testing is widely available through pathology labs. CKD is a growing health concern in India due to rising diabetes and hypertension rates. The Indian Society of Nephrology follows international CKD staging guidelines. Standard serum creatinine tests cost approximately ₹100-300.
Frequently Asked Questions
What is eGFR and why is it important?
eGFR (estimated Glomerular Filtration Rate) measures how well your kidneys filter blood. It is a key indicator of kidney function used to detect early kidney disease, monitor CKD progression, and guide medication dosing. A normal eGFR is 90 mL/min/1.73m² or above, though values decline naturally with age.
What is a normal eGFR by age?
A normal eGFR for young adults is 90-120 mL/min/1.73m². eGFR naturally decreases with age: people in their 40s may have 80-100, those in their 60s may have 70-90, and those over 70 may have 60-80. An eGFR below 60 for three months or more indicates chronic kidney disease.
How is eGFR calculated?
eGFR is calculated using formulas that incorporate serum creatinine, age, gender, and race. The CKD-EPI (2009) equation is the most accurate: eGFR = 141 × min(SCr/k, 1)^α × max(SCr/k, 1)^-1.209 × 0.993^Age × a × b. The MDRD equation is an alternative: eGFR = 175 × SCr^-1.154 × Age^-0.203 × a × b.
What is the difference between CKD-EPI and MDRD equations?
The CKD-EPI (2009) equation is more accurate than MDRD, especially at higher GFR values (above 60 mL/min/1.73m²). The MDRD equation tends to underestimate GFR in healthy individuals. CKD-EPI is now the recommended standard from the National Kidney Foundation and is used by most laboratories worldwide.
Can drinking water increase my eGFR?
No. Scientific studies have not found that higher water intake increases eGFR in the long term. Drinking more water will not slow the progression of kidney disease. However, staying adequately hydrated is important for overall kidney health.
What do the CKD stages mean?
CKD Stage 1 (eGFR 90+): Normal kidney function. Stage 2 (60-89): Mildly decreased. Stage 3a (45-59): Mildly to moderately decreased. Stage 3b (30-44): Moderately to severely decreased. Stage 4 (15-29): Severely decreased. Stage 5 (under 15): Kidney failure requiring dialysis or transplant. Early detection can slow progression.
How does race affect eGFR calculation?
The CKD-EPI and MDRD equations include a race coefficient for Black/African American individuals (1.159 for CKD-EPI, 1.212 for MDRD) because studies show they have higher average muscle mass and creatinine production. Some US labs have moved to race-free equations, but the 2009 CKD-EPI with race remains widely used worldwide.
How accurate is this calculator and can I rely on it for diagnosis?
This calculator uses standard medical formulas (CKD-EPI 2009 and MDRD) and provides reference information only. eGFR results should be verified by a healthcare professional through proper lab testing. This is for educational and reference purposes, not a substitute for professional medical advice, diagnosis, or treatment.