Calculates Body Fat Percentage based on AR 600-9 Standards.
Male
Female
Men: Measure at navel. Women: Measure at narrowest point.
Women only: Measure at widest point of buttocks.
Your Estimated Body Fat
0%
About the Army Body Fat Assessment
The United States Army uses the "Tape Test" method, as outlined in Army Regulation 600-9 (The Army Body Composition Program), to determine if a service member meets health and readiness standards. Unlike BMI, which only considers height and weight, the tape test estimates body composition by measuring specific circumferences.
Maximum Allowable Body Fat (AR 600-9)
Age Group
Male Max %
Female Max %
17–20
20%
30%
21–27
22%
32%
28–39
24%
34%
40+
26%
36%
How to Measure Correctly
Neck: Measure just below the larynx (Adam's Apple). Keep the tape perpendicular to the long axis of the neck.
Abdomen (Men): Measure horizontally at the level of the navel (belly button). Do not suck in.
Waist (Women): Measure at the narrowest part of the torso (above the navel and below the sternum).
Hips (Women): Measure at the widest point of the buttocks, ensuring the tape is parallel to the floor.
Height: Stand straight against a wall, barefoot, looking straight ahead.
Example Calculation
A 25-year-old male standing 70 inches tall, with a 16-inch neck and a 36-inch abdomen, would calculate as follows:
BF% = 86.010 * log10(36 – 16) – 70.041 * log10(70) + 36.76 Result: 19.5% Body Fat (Passes for age 21-27).
function toggleFemaleFields() {
var gender = document.getElementById("gender").value;
var hipContainer = document.getElementById("hip-container");
var waistLabel = document.getElementById("waist-label");
if (gender === "female") {
hipContainer.style.display = "block";
waistLabel.innerText = "Waist – Narrowest (inches)";
} else {
hipContainer.style.display = "none";
waistLabel.innerText = "Abdomen – Navel (inches)";
}
}
function calculateArmyBF() {
var gender = document.getElementById("gender").value;
var height = parseFloat(document.getElementById("height").value);
var neck = parseFloat(document.getElementById("neck").value);
var waist = parseFloat(document.getElementById("waist").value);
var hips = parseFloat(document.getElementById("hips").value);
var resultBox = document.getElementById("result-box");
var bfOutput = document.getElementById("bf-output");
var statusText = document.getElementById("status-text");
if (!height || !neck || !waist || (gender === "female" && !hips)) {
alert("Please enter all required measurements.");
return;
}
var bodyFat = 0;
if (gender === "male") {
// US Army Male Formula (Standard Units)
// %BF = 86.010 * log10(abdomen – neck) – 70.041 * log10(height) + 36.76
var circumDiff = waist – neck;
if (circumDiff <= 0) {
alert("Measurements invalid: Abdomen must be larger than neck.");
return;
}
bodyFat = (86.010 * Math.log10(circumDiff)) – (70.041 * Math.log10(height)) + 36.76;
} else {
// US Army Female Formula (Standard Units)
// %BF = 163.205 * log10(waist + hip – neck) – 97.684 * log10(height) – 78.387
var circumSum = waist + hips – neck;
if (circumSum <= 0) {
alert("Measurements invalid: Waist + Hips must be larger than neck.");
return;
}
bodyFat = (163.205 * Math.log10(circumSum)) – (97.684 * Math.log10(height)) – 78.387;
}
var finalBF = bodyFat.toFixed(1);
bfOutput.innerText = finalBF + "%";
resultBox.style.display = "block";
// Basic pass/fail interpretation (generic)
if (finalBF <= 0) {
statusText.innerText = "Check your measurements. Value is unrealistic.";
statusText.style.color = "red";
} else {
statusText.innerText = "Calculated using AR 600-9 official equations.";
statusText.style.color = "#4b5320";
}
}