What Are Sister Bra Sizes? Unlocking the Secrets of Bra Sizing

Finding the perfect bra can sometimes feel like searching for a needle in a haystack. With various brands, styles, and sizing systems, it's easy to get overwhelmed. However, there's a lesser-known concept in the world of bra fitting that can help you expand your options and find a more comfortable fit: sister sizes. In this blog post, we'll unravel the mystery behind sister sizes and how they can enhance your bra shopping experience.

Understanding Bra Sizes:

Before we dive into sister sizes, let's briefly recap how bra sizes work. A bra size consists of a combination of two measurements: the band size and the cup size. The band size corresponds to the measurement around your ribcage just beneath your breasts, while the cup size represents the difference between your band size and the measurement around the fullest part of your bust.

Traditionally, bra sizes follow a specific sequence, such as 32A, 34B, 36C, and so on. Each increase in band size usually comes with an increase in cup size. However, this linear sizing system can limit your options when searching for a well-fitting bra.

Introducing Sister Sizes:

Sister sizes are a range of bra sizes that have the same cup volume but differ in band size. In simpler terms, sister sizes are alternative sizes that can provide a similar fit even if the actual numbers differ. For example, if your usual size is 34C, your sister sizes would be 32D and 36B. These sizes maintain the same cup volume as your original size while accommodating different band sizes.

The concept of sister sizes allows for more flexibility when shopping for bras. If you find that your usual size isn't readily available or feels slightly uncomfortable, exploring sister sizes can open up a whole new world of options. It's important to note that while sister sizes have the same cup volume, the fit may still vary slightly due to differences in band length and shape.

How to Find Your Sister Sizes:

To determine your sister sizes, you need to understand the relationship between band size and cup size. When moving to a sister size with a smaller band, you should go up one cup size to maintain the same cup volume. Conversely, if you're moving to a sister size with a larger band, you should go down one cup size.

For example, if you usually wear a 34D and want to find your sister sizes, you would go up in band size to 36C (one size larger) or down to 32DD (one size smaller). This way, you can experiment with different band sizes while ensuring that the cup volume remains consistent. To help you find a great fitting bra, we have included 8 alternative sister sizes in the chart below:

sister bra sizing chart to help you find your perfect fit

Benefits of Exploring Sister Sizes:

  1. Increased options: Sister sizes can expand your bra shopping options, especially if your preferred size is not available. By trying on sister sizes, you might discover that a slightly different size provides a better fit and improved comfort.
  2. Accommodating weight fluctuations: Our bodies are not static, and weight fluctuations are common. Sister sizes can be particularly useful during times when your weight changes, allowing you to find a suitable bra size without needing a complete overhaul of your lingerie collection.
  3. Bra style variations: Different brands and bra styles may have slight variations in sizing. Exploring sister sizes can help you find the perfect fit within a particular brand or style, even if the sizes seem to deviate from your usual measurements.

Sister sizes are a valuable tool in the world of bra fitting, providing more options and flexibility when it comes to finding the perfect fit. By understanding the relationship between band size and cup size, you can confidently explore alternative sizes and discover bras that offer superior comfort and support. So the next time you're on the hunt for a new