Bra Cup Size Calculator Us

US Bra Cup Size Calculator

Use this calculator to determine your estimated US bra band and cup size. Accurate measurements are key to finding a comfortable and supportive bra.

Measure snugly around your rib cage, directly under your bust.
Measure around the fullest part of your bust, usually over your nipples.
function calculateBraSize() { var underbustSnug = parseFloat(document.getElementById('underbustSnug').value); var bustFullest = parseFloat(document.getElementById('bustFullest').value); var resultDiv = document.getElementById('braResult'); if (isNaN(underbustSnug) || isNaN(bustFullest) || underbustSnug <= 0 || bustFullest <= 0) { resultDiv.innerHTML = "Please enter valid positive numbers for both measurements."; return; } if (bustFullest < underbustSnug) { resultDiv.innerHTML = "Your fullest bust measurement cannot be less than your underbust measurement. Please re-enter your measurements."; return; } // Step 1: Calculate Band Size (US System) // Round the snug underbust measurement to the nearest whole inch. // If the result is an odd number, add 1 to make it an even band size. var bandSize = Math.round(underbustSnug); if (bandSize % 2 !== 0) { // If bandSize is odd bandSize += 1; } // Step 2: Calculate Cup Difference var cupDifference = bustFullest – bandSize; // Step 3: Determine Cup Letter (US System) var cupLetter = ""; var cupSizes = ["AA", "A", "B", "C", "D", "DD", "DDD (F)", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P"]; // Round the cup difference to the nearest whole number for cup index var cupIndex = Math.round(cupDifference); if (cupIndex = cupSizes.length) { // If the difference is larger than our defined cup sizes, cap it at the largest cupIndex = cupSizes.length – 1; } cupLetter = cupSizes[cupIndex]; resultDiv.innerHTML = "Your estimated US Bra Size: " + bandSize + cupLetter + ""; }

Understanding Your Bra Size

Finding the right bra size is crucial for comfort, support, and the overall look of your clothing. Many women wear the wrong bra size, often due to outdated measurement methods or inconsistencies between brands. This calculator uses a common modern US sizing approach to give you an estimated starting point.

How to Measure Accurately:

  1. Snug Underbust Measurement: Stand upright, wearing a non-padded bra or no bra. Wrap a soft measuring tape around your back, directly under your bust where your bra band sits. Make sure the tape is level and snug, exhaling to get the smallest measurement. This measurement helps determine your band size.
  2. Fullest Bust Measurement: While still standing, measure around the fullest part of your bust, usually over your nipples. Ensure the tape is level and not too tight or too loose. This measurement, combined with your underbust, helps determine your cup size.

The Calculation Explained:

  • Band Size: In the US system, bra bands are typically even numbers (e.g., 30, 32, 34). Our calculator takes your snug underbust measurement, rounds it to the nearest whole inch, and then adjusts it to the nearest even number. For example, if your underbust is 31.5 inches, it rounds to 32 inches. If it's 30.1 inches, it rounds to 30 inches.
  • Cup Size: Your cup size is determined by the difference between your fullest bust measurement and your calculated band size. Each inch of difference corresponds to a cup letter:
    • 0 inches: AA
    • 1 inch: A
    • 2 inches: B
    • 3 inches: C
    • 4 inches: D
    • 5 inches: DD
    • 6 inches: DDD (F)
    • And so on…

Important Considerations:

Bra sizing is not an exact science, and this calculator provides an estimate. Here's why:

  • Brand Variation: Sizes can vary significantly between different bra brands. What's a 34C in one brand might feel like a 32D or 36B in another.
  • Bra Style: Different bra styles (e.g., push-up, balconette, full coverage) can fit differently even within the same size.
  • Body Shape: Your unique breast shape and body proportions can influence how a bra fits.
  • Comfort is Key: The best bra size is the one that feels most comfortable and provides the best support without digging, gapping, or riding up.

Next Steps:

Use your calculated size as a starting point. When trying on bras:

  • The band should be snug and level all the way around your back, not riding up. You should be able to fit two fingers comfortably under the band.
  • The cups should fully encapsulate your breasts without gapping or spilling over.
  • The center gore (the part between the cups) should lie flat against your sternum.
  • The straps should provide minimal lift; most of the support should come from the band.

Don't be afraid to try "sister sizes" (e.g., if you're a 34C, try a 32D or 36B) if your calculated size doesn't feel quite right. Happy bra shopping!

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