Enter your measurements to find your perfect fit (Inches)
Your Estimated Bra Size is:
Note: Fit may vary by brand and style.
How to Measure Your Bra Size at Home
Finding the right bra size is essential for comfort, posture, and confidence. Over 80% of women wear the wrong size. Follow these steps to get accurate measurements:
1. Measure Your Underbust (Band Size)
Wrap a soft measuring tape around your ribcage, directly under your bust. Ensure the tape is level and snug, but not digging in. Exhale deeply to get the most accurate measurement. This number determines your band size.
2. Measure Your Bust (Cup Size)
Measure around the fullest part of your chest. The tape should be parallel to the ground and rest lightly against your skin without compressing the breast tissue.
The Math Behind the Calculator
This calculator uses the modern "snug underbust" method, which is the standard for most UK and US lingerie brands:
Band Size: If your underbust measurement is an even number, that is usually your band size. If it is an odd number, we round up to the nearest even number.
Cup Size: We calculate the difference between your bust measurement and your band size. Each inch of difference represents one cup letter (1″ = A, 2″ = B, 3″ = C, etc.).
Common Bra Size Fitting Issues
Band riding up: The band is too big. Try a smaller band size.
Spillage (Quad-boob): The cups are too small. Try one cup size larger.
Gapping in cups: The cups are too large, or the style is wrong for your shape.
Straps digging in: Usually means the band is too loose and isn't providing enough support.
function calculateBraSize() {
var underbust = parseFloat(document.getElementById("underbust").value);
var bust = parseFloat(document.getElementById("bust").value);
var resultDiv = document.getElementById("braResult");
var sizeOutput = document.getElementById("sizeOutput");
if (isNaN(underbust) || isNaN(bust) || underbust <= 0 || bust <= 0) {
alert("Please enter valid positive measurements.");
return;
}
if (bust <= underbust) {
alert("Bust measurement must be larger than underbust measurement.");
return;
}
// Calculate Band Size
// Modern method: Round to nearest even number
var bandSize;
var roundedUnderbust = Math.round(underbust);
if (roundedUnderbust % 2 === 0) {
bandSize = roundedUnderbust;
} else {
bandSize = roundedUnderbust + 1;
}
// Calculate Cup Difference
var diff = Math.round(bust – bandSize);
var cupSize = "";
var cups = [
"AA", // 0
"A", // 1
"B", // 2
"C", // 3
"D", // 4
"DD (E)", // 5
"DDD (F)", // 6
"G", // 7
"H", // 8
"I", // 9
"J", // 10
"K" // 11
];
if (diff = cups.length) {
cupSize = "K+";
} else {
cupSize = cups[diff];
}
sizeOutput.innerHTML = bandSize + cupSize;
resultDiv.style.display = "block";
resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}