Calculating Glomerular Filtration Rate

GFR Calculator (CKD-EPI 2021)

Male Female

Estimated GFR Result

mL/min/1.73 m²

Understanding Your GFR Result

Glomerular Filtration Rate (GFR) is the best test to measure your level of kidney function and determine your stage of kidney disease. It calculates how much blood passes through the glomeruli (tiny filters in the kidneys) each minute.

The CKD-EPI 2021 Equation

This calculator utilizes the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation. This is the current medical standard which does not include a race coefficient, providing a more equitable assessment of kidney health based on age, sex, and serum creatinine levels.

CKD Stages Table

Stage GFR Level Description
Stage 1 90 or higher Normal function (or kidney damage with normal GFR)
Stage 2 60 – 89 Mildly decreased function
Stage 3a 45 – 59 Mild to moderate decrease
Stage 3b 30 – 44 Moderate to severe decrease
Stage 4 15 – 29 Severely decreased function
Stage 5 Less than 15 Kidney failure (ESRD)

Calculation Example

If a 50-year-old male has a serum creatinine of 1.2 mg/dL, his GFR would be approximately 78 mL/min/1.73 m², placing him in Stage 2 (Mildly decreased function). If a 65-year-old female has a serum creatinine of 2.0 mg/dL, her GFR would be approximately 26 mL/min/1.73 m², indicating Stage 4 (Severely decreased function).

Note: This calculator is for informational purposes only and should not replace professional medical advice. Always consult with a healthcare provider regarding kidney health and lab results.

function calculateGFR() { var scr = parseFloat(document.getElementById('serumCreatinine').value); var age = parseFloat(document.getElementById('patientAge').value); var gender = document.getElementById('patientGender').value; var resultDiv = document.getElementById('gfrResult'); var valueDiv = document.getElementById('gfrValue'); var stageDiv = document.getElementById('gfrStage'); if (isNaN(scr) || isNaN(age) || scr <= 0 || age = 90) { stageText = "Stage 1: Normal or high function"; stageColor = "#28a745"; } else if (gfr >= 60) { stageText = "Stage 2: Mildly decreased function"; stageColor = "#8bc34a"; } else if (gfr >= 45) { stageText = "Stage 3a: Mildly to moderately decreased function"; stageColor = "#ffc107"; textColor = "#333"; } else if (gfr >= 30) { stageText = "Stage 3b: Moderately to severely decreased function"; stageColor = "#fd7e14"; } else if (gfr >= 15) { stageText = "Stage 4: Severely decreased function"; stageColor = "#dc3545"; } else { stageText = "Stage 5: Kidney failure"; stageColor = "#721c24"; } stageDiv.innerHTML = stageText; stageDiv.style.backgroundColor = stageColor; stageDiv.style.color = textColor; resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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