Kidney Function Calculator (eGFR)

Estimate your glomerular filtration rate (eGFR) using the CKD-EPI formula.

Kidney Function

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eGFR (mL/min/1.73m2)

CKD Stage

Stage 1 (Normal)

Kidney Function

CKD Stages

Kidney Function

MetricValue
eGFR (mL/min/1.73m2)91.7
Serum Creatinine (mg/dL)1.00
CKD StageStage 1 (Normal)
Age50
GenderMale

Understanding Kidney Function

The estimated Glomerular Filtration Rate (eGFR) is the best overall measure of kidney function. It estimates how much blood passes through the glomeruli (the filtering units) each minute. The CKD-EPI 2021 equation is the current gold standard for calculating eGFR, using serum creatinine, age, and gender. Unlike the older MDRD equation, CKD-EPI 2021 no longer includes a race coefficient, making it more equitable. A normal eGFR is 90 or above. CKD is classified into 5 stages: Stage 1 (eGFR 90+ with kidney damage markers), Stage 2 (60-89), Stage 3a (45-59), Stage 3b (30-44), Stage 4 (15-29), and Stage 5 (below 15, kidney failure). Early detection of declining kidney function is crucial because lifestyle changes and medications can significantly slow progression.

Practical Example

Scenario: A 65-year-old male with serum creatinine of 1.4 mg/dL.

Step 1: Using CKD-EPI 2021: kappa=0.9, alpha=-0.302

Step 2: eGFR = 142 x (1.4/0.9)^-0.302 x (1.4/0.9)^-1.2 x 0.9938^65 x 1

Step 3: eGFR is approximately 52 mL/min/1.73m2 (Stage 3a - Mild-Moderate CKD)

Regular monitoring and nephrology referral recommended.

Preguntas Frecuentes

What is a normal eGFR?

A normal eGFR is 90 mL/min/1.73m2 or above. However, eGFR naturally decreases with age, and values above 60 are generally considered adequate for most people.

What causes low eGFR?

Common causes include diabetes, high blood pressure, glomerulonephritis, polycystic kidney disease, prolonged urinary tract obstruction, and certain medications.

Can kidney function improve?

Acute kidney injury may be reversible. Chronic kidney disease typically cannot be reversed, but progression can be slowed through blood pressure control, blood sugar management, and dietary changes.

How accurate is the eGFR calculation?

The CKD-EPI equation is reasonably accurate for most adults. It may be less accurate for very muscular individuals, amputees, or those with unusual body compositions. A 24-hour creatinine clearance test is more precise.

When should I see a nephrologist?

Referral is recommended for eGFR below 30, rapidly declining eGFR, proteinuria, or unexplained kidney abnormalities. Early referral improves outcomes.

Disclaimer: This calculator uses the CKD-EPI 2021 equation for estimation. It is not a substitute for professional medical evaluation. Individual results may vary based on muscle mass, diet, and other factors.

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