Glomerular Filtration Rate (GFR) is the best way to measure your level of kidney function and determine your stage of kidney disease. It is calculated based on your serum creatinine levels, age, and sex.
The CKD-EPI 2021 Equation
This tool uses the 2021 CKD-EPI creatinine equation, which is currently recommended by the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) because it does not include race as a factor in the calculation.
Chronic Kidney Disease (CKD) Stages:
Stage
eGFR Range
Description
Stage 1
90+
Normal or high 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
< 15
Kidney failure (ESRD)
Medical Disclaimer: This calculator is for educational purposes only. Results should be interpreted by a healthcare professional.
function calculateGFR() {
var scr = parseFloat(document.getElementById('creatinine').value);
var age = parseFloat(document.getElementById('age').value);
var gender = document.getElementById('gender').value;
var resultDiv = document.getElementById('result-container');
var gfrValueDisplay = document.getElementById('gfr-value');
var gfrStageDisplay = document.getElementById('gfr-stage');
var gfrDescDisplay = document.getElementById('gfr-desc');
if (isNaN(scr) || isNaN(age) || scr <= 0 || age = 90) {
stage = "Stage 1";
desc = "Your GFR suggests normal or high kidney function. However, if there are other signs of kidney damage (like protein in urine), it may still indicate Stage 1 CKD.";
color = "#28a745";
} else if (finalGfr >= 60) {
stage = "Stage 2";
desc = "Your GFR is mildly decreased. This is common with aging, but if other signs of kidney damage are present, it is considered Stage 2 CKD.";
color = "#8bc34a";
} else if (finalGfr >= 45) {
stage = "Stage 3a";
desc = "Your GFR indicates a mild to moderate loss of kidney function. You should consult a doctor to monitor your kidney health.";
color = "#ffc107";
} else if (finalGfr >= 30) {
stage = "Stage 3b";
desc = "Your GFR indicates a moderate to severe loss of kidney function. Medical follow-up is important to prevent further decline.";
color = "#fd7e14";
} else if (finalGfr >= 15) {
stage = "Stage 4";
desc = "Your GFR indicates a severe loss of kidney function. This is a serious stage that requires close management by a nephrologist.";
color = "#dc3545";
} else {
stage = "Stage 5";
desc = "Your GFR indicates kidney failure or near failure. Immediate medical consultation and discussion of treatment options like dialysis are necessary.";
color = "#721c24";
}
gfrStageDisplay.innerText = stage;
gfrStageDisplay.style.backgroundColor = color;
gfrDescDisplay.innerText = desc;
// Smooth scroll to result
resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}