Find your perfect bra size by measuring your underbust and bust. Follow the instructions below for accurate results.
Measure snugly around your rib cage directly under your breasts. This is your band size.
Measure around the fullest part of your bust, keeping the tape parallel to the floor.
Your Estimated Bra Size:
This is an estimation. Professional fitting is recommended for the best fit.
Understanding Bra Sizing
Finding the right bra size is crucial for comfort, support, and the overall appearance of your silhouette. A well-fitting bra can prevent back pain, shoulder strain, and discomfort, while an ill-fitting one can lead to a host of problems.
The bra sizing system is based on two primary measurements:
Band Size: This is determined by measuring the circumference of your rib cage directly under your breasts. The tape measure should be snug but comfortable. The number you get (typically in inches) is your band size. For example, a measurement of 32 inches usually corresponds to a 32 band size.
Cup Size: This is determined by the difference between your bust measurement (taken at the fullest part of your chest) and your band measurement. The difference in inches dictates the cup letter.
The Calculation Behind the Calculator
Our calculator uses a standard method to estimate your bra size:
Band Size Determination: The calculator takes your "Underbust Measurement" directly as the band size. Some systems round to the nearest even number or use a specific sizing chart to convert direct measurements, but for simplicity, we use the direct measurement here.
Cup Size Calculation: The calculator finds the difference between your "Bust Measurement" and your "Underbust Measurement". This difference is then used to determine the cup size based on the following common guidelines:
0-1 inch difference: AA Cup
1 inch difference: A Cup
2 inches difference: B Cup
3 inches difference: C Cup
4 inches difference: D Cup
5 inches difference: DD (or E) Cup
6 inches difference: DDD (or F) Cup
And so on, generally adding a cup size for each additional inch.
The final estimated bra size is presented as "Band Size Cup Size" (e.g., 34C).
Why Professional Fitting Matters
While this calculator provides a helpful starting point, it's important to remember that bra sizing can vary significantly between brands and even between different styles within the same brand. Factors like breast shape, breast tissue density, and bra construction can all influence how a bra fits. A professional bra fitter can assess these nuances and help you find a bra that offers the best possible support, comfort, and shape.
Common Fitting Issues and What They Might Mean:
Band rides up: Band is too loose. Try a smaller band size.
Cups overflow: Cups are too small. Try a larger cup size.
Straps dig in: Band might be too loose, causing straps to carry too much weight. Or, the cup fit isn't right.
Gaps in the cups: Cups are too large. Try a smaller cup size.
Underwire not flat against the ribcage: Band or cup size may be incorrect, or the bra shape doesn't match your breast shape.
Use this calculator as a guide to begin your journey to finding a perfectly fitting bra!
function calculateBraSize() {
var underbustInput = document.getElementById("underbustMeasurement");
var bustInput = document.getElementById("bustMeasurement");
var resultDiv = document.getElementById("result");
var resultValueSpan = document.getElementById("result-value");
var resultBandPara = document.getElementById("result-band");
var resultCupPara = document.getElementById("result-cup");
var underbust = parseFloat(underbustInput.value);
var bust = parseFloat(bustInput.value);
// Input validation
if (isNaN(underbust) || underbust <= 0) {
alert("Please enter a valid positive number for your underbust measurement.");
return;
}
if (isNaN(bust) || bust <= 0) {
alert("Please enter a valid positive number for your bust measurement.");
return;
}
if (bust = 0 && cupDifference = 1 && cupDifference = 2 && cupDifference = 3 && cupDifference = 4 && cupDifference = 5 && cupDifference = 6 && cupDifference = 7 && cupDifference = 8 && cupDifference < 9) {
cupSize = "H";
} else {
cupSize = "I+"; // For larger differences
}
var estimatedSize = bandSize + cupSize;
resultValueSpan.textContent = estimatedSize;
resultBandPara.textContent = "Band: " + bandSize + " inches";
resultCupPara.textContent = "Cup: " + cupSize;
resultDiv.style.display = "block";
}