Cup Size Calculator Us

Your guide to finding the perfect bra fit.

Measurement Visualization

Visual comparison of your band and bust measurements.

US Cup Size Chart

This table shows how the difference between bust and band measurement translates to a cup letter.

Difference (Inches)	US Cup Size
< 1″	AA
1″	A
2″	B
3″	C
4″	D
5″	DD (or E)
6″	DDD (or F)
7″	G
8″	H
9″	I
10″	J

What is a US Cup Size Calculator?

A cup size calculator us is a specialized tool designed to help you determine your correct bra size based on standard US sizing conventions. Finding the right bra size is crucial for comfort, support, and overall breast health. Studies show that a large percentage of women wear incorrectly fitted bras, which can lead to issues like back pain, strap slipping, and poor posture. This calculator simplifies the process by taking your specific body measurements—your band (underbust) and bust—to provide an accurate, estimated bra size.

US Cup Size Formula and Explanation

The calculation for US bra sizes involves two key steps: determining the band size and then the cup size. The formula is straightforward:

1. Band Size: This is determined by your underbust measurement. Most modern methods recommend rounding your raw underbust measurement to the nearest even number. For example, if you measure 31 inches, your band size would be 32.
2. Cup Size: The cup size is found by subtracting the band measurement from the bust measurement. The resulting difference in inches corresponds to a letter.

Cup Size (Letter) = Bust Measurement – Band Measurement (Raw)

Variables used in the cup size calculator us.

Variable	Meaning	Unit	Typical Range
Band Measurement	The measurement around your ribcage, just under your breasts.	Inches / cm	28 – 48 inches
Bust Measurement	The measurement around the fullest part of your breasts.	Inches / cm	30 – 55 inches
Calculated Band Size	Your band measurement rounded to the nearest even number.	Inches	28, 30, 32, etc.
Bust-Band Difference	The key value used to determine the cup letter.	Inches	0 – 10+ inches

Practical Examples

Example 1:

• Inputs:
  • Band Measurement: 31.5 inches
  • Bust Measurement: 37 inches
• Calculation:
  • Band Size = 31.5″ rounded to the nearest even number is 32.
  • Difference = 37″ (Bust) – 31.5″ (Band) = 5.5 inches.
  • A 5.5-inch difference corresponds to a DD or E cup.
• Result: 32DD

Example 2:

• Inputs:
  • Band Measurement: 34 inches
  • Bust Measurement: 37 inches
• Calculation:
  • Band Size = 34″ is already an even number, so it's 34.
  • Difference = 37″ (Bust) – 34″ (Band) = 3 inches.
  • A 3-inch difference corresponds to a C cup.
• Result: 34C

How to Use This Cup Size Calculator US

Using this calculator is a simple, three-step process:

1. Select Your Units: Start by choosing whether you will be entering your measurements in inches or centimeters. The calculator will automatically handle any necessary conversions.
2. Enter Band Measurement: While braless or wearing a non-padded bra, measure around your ribcage directly underneath your breasts. The tape should be level and snug, but not too tight. Enter this number into the "Band Measurement" field.
3. Enter Bust Measurement: Next, measure loosely around the fullest part of your chest, typically at nipple level. Ensure the tape measure is straight across your back. Enter this value into the "Bust Measurement" field.
4. Interpret the Results: The calculator will instantly display your estimated US bra size, including the calculated band size and cup letter. It also shows intermediate values like the exact bust-band difference to help you understand how the result was derived.

Key Factors That Affect Bra Size

While a cup size calculator us provides a great starting point, several other factors can influence the perfect fit:

• Sister Sizes: These are alternate sizes where the cup volume remains the same even if the band size and cup letter change. For example, if a 34C is too loose in the band, you could try its sister size, 32D.
• Brand and Style Variation: Bra sizing is not perfectly standardized across all manufacturers. A 34C in one brand might fit differently than in another. Different styles (e.g., plunge, full-cup, t-shirt bra) also fit differently.
• Breast Shape: Shape matters as much as size. Breasts can be round, teardrop, slender, or asymmetrical. Certain bra styles are better suited for specific shapes.
• Time of the Month: Hormonal fluctuations during the menstrual cycle can cause breasts to swell, temporarily changing your bra size.
• Band Tightness: The bra band provides most of the support. It should be snug and level across your back. If it rides up, the band is too loose.
• Cup Fit: There should be no gaping at the top of the cups and no "spillage" over the top or sides. The underwire should sit flat against your ribcage.

Frequently Asked Questions (FAQ)

1. How often should I measure my bra size?

It's recommended to measure yourself every 6-12 months, or after any significant changes in your body such as weight loss/gain, pregnancy, or starting a new fitness routine.

2. What's the difference between DD and E?

In US sizing, DD is often used to represent a 5-inch difference between the bust and band. E is the equivalent in UK sizing and is sometimes used interchangeably in the US. Similarly, DDD in the US is equivalent to an F cup.

3. What if I get an odd number for my band measurement?

This calculator follows the modern sizing method of rounding to the nearest *even* number. Some older methods suggest adding 4 or 5 inches, but this can often lead to an incorrect, unsupportive fit.

4. What are sister sizes?

Sister sizes are groups of bra sizes with the same cup volume. For example, a 32D, 34C, and 36B all hold roughly the same amount of breast tissue. Knowing your sister size is useful if a particular bra doesn't fit quite right in the band. If you need a tighter band, you go down a band size and up a cup size (e.g., from 34C to 32D).

5. Can I measure myself without a measuring tape?

Yes. You can use a non-stretchy piece of string or ribbon to take the measurements and then measure the string with a ruler.

6. My calculator result is very different from my current size. Is it right?

It's very possible. Since a majority of women wear the wrong size, the calculated result might seem surprising. It's best to treat the result from this cup size calculator us as a new starting point and try on bras in that size and its sister sizes to confirm the best fit.

7. Does breast shape matter more than size?

Both are equally important for a good fit. Your size measurements determine the volume, but your shape (e.g., shallow, projected, wide-set) determines which bra *styles* will work best for you.

8. Why does the band ride up my back?

This is the most common sign that your band size is too large. The band should be firm and anchor itself horizontally across your back to provide support. Try a smaller band size (and likely a larger cup size, your sister size).