Navy Body Fat Calculator
.navy-calc-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e1e1e1;
border-radius: 12px;
background-color: #ffffff;
box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
.navy-calc-header {
text-align: center;
margin-bottom: 30px;
}
.navy-calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 25px;
}
.navy-calc-input-group {
display: flex;
flex-direction: column;
}
.navy-calc-input-group label {
font-weight: 600;
margin-bottom: 8px;
color: #333;
}
.navy-calc-input-group input, .navy-calc-input-group select {
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
}
.navy-calc-btn {
grid-column: span 2;
background-color: #1a365d;
color: white;
padding: 15px;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s;
}
.navy-calc-btn:hover {
background-color: #2c5282;
}
.navy-calc-result {
margin-top: 30px;
padding: 20px;
border-radius: 8px;
background-color: #f7fafc;
display: none;
text-align: center;
}
.navy-calc-result-value {
font-size: 32px;
font-weight: 800;
color: #2b6cb0;
margin: 10px 0;
}
.navy-calc-category {
font-weight: 600;
font-size: 18px;
color: #4a5568;
}
.navy-article {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.navy-article h2 {
color: #1a365d;
border-bottom: 2px solid #edf2f7;
padding-bottom: 10px;
}
.navy-article table {
width: 100%;
border-collapse: collapse;
margin: 20px 0;
}
.navy-article th, .navy-article td {
padding: 12px;
border: 1px solid #e2e8f0;
text-align: left;
}
.navy-article th {
background-color: #f8fafc;
}
@media (max-width: 600px) {
.navy-calc-grid {
grid-template-columns: 1fr;
}
.navy-calc-btn {
grid-column: span 1;
}
}
function toggleHipInput() {
var gender = document.getElementById('navyGender').value;
var hipGroup = document.getElementById('hipGroup');
if (gender === 'female') {
hipGroup.style.display = 'flex';
} else {
hipGroup.style.display = 'none';
}
}
function updateLabels() {
var unit = document.getElementById('navyUnits').value;
var suffix = unit === 'metric' ? '(cm)' : '(inches)';
document.getElementById('heightLabel').innerText = 'Height ' + suffix;
document.getElementById('neckLabel').innerText = 'Neck Circumference ' + suffix;
document.getElementById('waistLabel').innerText = 'Waist Circumference ' + suffix;
document.getElementById('hipLabel').innerText = 'Hip Circumference ' + suffix;
}
function calculateNavyFat() {
var gender = document.getElementById('navyGender').value;
var units = document.getElementById('navyUnits').value;
var height = parseFloat(document.getElementById('navyHeight').value);
var neck = parseFloat(document.getElementById('navyNeck').value);
var waist = parseFloat(document.getElementById('navyWaist').value);
var hip = parseFloat(document.getElementById('navyHip').value) || 0;
if (!height || !neck || !waist || (gender === 'female' && !hip)) {
alert('Please fill in all required fields with valid numbers.');
return;
}
// Convert to inches for standard formula if metric
var h = height;
var n = neck;
var w = waist;
var hp = hip;
if (units === 'metric') {
h = height / 2.54;
n = neck / 2.54;
w = waist / 2.54;
hp = hip / 2.54;
}
var bodyFat = 0;
if (gender === 'male') {
// Navy Formula for Men (using inches)
// 86.010*LOG10(waist-neck) – 70.041*LOG10(height) + 36.76
if (w <= n) {
alert('Waist must be larger than neck circumference.');
return;
}
bodyFat = 86.010 * Math.log10(w – n) – 70.041 * Math.log10(h) + 36.76;
} else {
// Navy Formula for Women (using inches)
// 163.205*LOG10(waist+hip-neck) – 97.684*LOG10(height) – 78.387
if ((w + hp) <= n) {
alert('Waist + Hip must be larger than neck circumference.');
return;
}
bodyFat = 163.205 * Math.log10(w + hp – n) – 97.684 * Math.log10(h) – 78.387;
}
displayResults(bodyFat, gender);
}
function displayResults(bf, gender) {
var resultDiv = document.getElementById('navyResult');
var valDiv = document.getElementById('resultValue');
var statusDiv = document.getElementById('resultStatus');
bf = Math.max(0, bf); // No negative body fat
valDiv.innerText = bf.toFixed(1) + "%";
var status = "";
if (gender === 'male') {
if (bf < 6) status = "Essential Fat";
else if (bf < 14) status = "Athlete";
else if (bf < 18) status = "Fitness";
else if (bf < 25) status = "Average";
else status = "Obese";
} else {
if (bf < 14) status = "Essential Fat";
else if (bf < 21) status = "Athlete";
else if (bf < 25) status = "Fitness";
else if (bf < 32) status = "Average";
else status = "Obese";
}
statusDiv.innerText = "Category: " + status;
resultDiv.style.display = 'block';
resultDiv.scrollIntoView({ behavior: 'smooth' });
}