Bra Sizes Explained

Bra sizes, consisting of a band size (number) and cup size (letter), indicate the dimensions of a woman’s chest and breast volume for example k cup bras (as shown here on the Uplifted Lingerie website) could be referred to as 42k. The band size represents the measurement around the rib cage in inches, while the cup size reflects the difference between the rib cage and bust measurements, with each letter typically representing a one-inch increment.

History of Bra Sizing Systems

The modern bra sizing system has its roots in the early 20th century. Key developments include:

• 1910s-1920s: First use of cup sizes, though not standardized.
• 1932: S.H. Camp and Company introduces letter sizing (A, B, C, D) to indicate breast pendulousness.
• 1935: Warner’s introduces the Alphabet Bra with cup sizes based on breast volume.
• 1940s: Band sizes become popular, creating the number-letter combination still used today.
• 1950s: Sears catalog finally applies cup sizes to bras.

Initially, bras were one-size-fits-all using stretchy materials. The introduction of distinct cup sizes and adjustable bands in the 1930s revolutionized fit and comfort.

However, sizing standards varied between manufacturers until more recently. This evolution reflects ongoing efforts to better accommodate diverse body types and breast shapes.

Understanding Sister Sizes

Sister sizes are bra sizes that have the same cup volume but different band sizes. This concept is crucial for finding the right fit when adjusting between band sizes. Here’s how sister sizing works:

• Moving up a band size requires going down a cup size to maintain the same volume (e.g., 32D to 34C).
• Moving down a band size requires going up a cup size (e.g., 34C to 32D).

Sister sizes have identical cup volumes despite different letter designations (e.g., 28E, 30D, and 32C). Understanding sister sizes allows for flexibility when shopping, especially when a preferred size is unavailable or when transitioning between brands with slightly different sizing systems.

However, it’s important to note that while cup volume remains constant, the overall fit and support can vary due to differences in band tightness and cup shape across sister sizes.

Impact of Bra Fabric on Fit

The fabric used in bra construction significantly impacts fit and comfort. Different materials offer varying levels of stretch, support, and breathability:

• Satin spandex tricot provides a shiny, comfortable finish but can be challenging to fit due to its one-directional stretch.
• Power mesh offers excellent support and is often used in the back band, where 80% of a bra’s support comes from.
• Sheer cup lining is ideal for mock-ups and fittings due to its versatility.
• 40 denier tricot, with some stretch in both directions, tends to yield a smoother fit compared to fabrics with stretch in only one direction.

The direction of stretch (DOGS) in fabric is crucial for proper bra fit. Placing the DOGS vertically on stretch bra cups can affect compression and shape, while horizontal stretch around the body is typically recommended for the back band.

Fabric choice can also impact underwire fit, as tension on the wing can cause the wire to “spring” open, affecting the overall fit of the bra.

Bra Size Range

Bra sizes ranging from 28A to 42GG represent a wide spectrum of body types and breast volumes. This range encompasses:

• Band sizes from 28 to 42 inches, accommodating various ribcage measurements.
• Cup sizes from A (smallest) to GG (larger), reflecting different breast volumes relative to band size.

The 28A size typically fits individuals with a very slim frame and small bust, while 42GG caters to those with a larger ribcage and significantly more breast tissue. It’s important to note that cup size is relative to band size—a 28GG has the same cup volume as a 42D, despite sounding much larger.

Some key points about this size range:

• 28 bands are considered specialty sizes and may be harder to find in mainstream stores.
• Larger cup sizes (DD and above) often require more supportive construction techniques.
• The same letter can represent very different breast volumes across band sizes (e.g., 28G vs 42G).

This wide range of sizes illustrates the diversity of body shapes and the importance of proper fitting to ensure comfort and support.

UK vs US Sizing

Bra sizing systems in the UK and USA share similarities but have key differences, particularly in cup size labeling. This table provides a comparison of UK and US bra sizes:

The band sizes in UK and US systems are identical, using even numbers (e.g., 28, 30, 32). The main differences occur in cup sizes, especially for larger busts:

• UK sizing uses double letters (FF, GG, HH) after E, while US sizing typically doesn’t.
• US cup sizes often have multiple labels for the same size (e.g., DDD/F), which can cause confusion.
• After D, UK cup sizes progress as DD, E, F, FF, G, GG, while US sizes go DD, DDD/F, G, H, I, J.

A UK E cup is equivalent to a US DDD/F cup, and the difference increases with larger sizes.

When shopping for bras, it’s crucial to know which sizing system the brand uses. Many UK brands are available in the US, so understanding both systems helps ensure a proper fit.

Always refer to the brand’s specific size chart, as there can be slight variations between manufacturers even within the same country’s sizing system.

Conclusion

Bra sizing is a complex system combining band size (the ribcage measurement) and cup size (the difference between the ribcage and bust measurements) to accommodate a wide variety of body types and breast shapes.

Over the past century, the bra sizing system has evolved significantly, from one-size-fits-all designs to today’s diverse range of sizes and materials that offer better fit and support.

Understanding sister sizes, which allow for flexibility when adjusting band sizes, is essential for finding the right fit.

Additionally, fabric choice plays a significant role in the comfort and fit of a bra, impacting stretch, support, and shaping.

Bra sizes range from 28A to 42GG, highlighting the importance of proper fitting for both small and large busts.

The differences between UK and US sizing systems, especially in cup labeling, can sometimes lead to confusion, making it vital to check size charts specific to each brand.

Overall, finding the right bra size and style requires knowledge of sizing, fabrics, and sister sizes to ensure comfort, support, and the best fit for your body.