Why Brand Sizing Differs
Not all 34Cs are created equal. A 34C from Victoria's Secret may fit differently than a 34C from Panache, Freya, or Wacoal. Understanding why helps you shop smarter and find your true size faster.
Brand sizing variations come from several factors. Each brand designs for a slightly different "fit model" (the person they prototype on), uses different materials with varying stretch properties, and follows slightly different grading rules when scaling patterns up and down from their sample size.
European brands like Chantelle and Empreinte tend to use firmer bands with less stretch, while American brands like Victoria's Secret often use stretchier materials. UK brands like Panache and Freya typically have deeper, more projected cups compared to US brands. Japanese brands run significantly smaller in both band and cup than Western brands. These differences mean your "true" size can vary by 1-2 band sizes and 1-3 cup letters depending on the brand.
How to Use the Calibration Tool
The calibration table below lets you set per-brand offsets. Each offset tells the converter how a specific brand's sizing runs relative to standard US sizing:
- Band Offset: How the band runs. A positive value (+1) means the brand's bands run tight — you may want to size up in the band. A negative value (-1) means the brand's bands run loose — you may want to size down. Zero means the brand runs true to standard.
- Cup Offset: How the cup runs. A positive value (+1) means the brand's cups run small — you may want to go up a cup. A negative value (-1) means the brand's cups run large. Zero means true to standard.
For example, if you typically wear a 34DD in US sizing but find that Panache bras feel tight in the band, set Panache's band offset to +1. The converter will then suggest a 36D when converting your US 34DD to Panache sizing. Your calibrations are saved locally in your browser and will persist between visits.
How to Determine Your Brand Offsets
To figure out the right offsets for a brand you wear:
- Start with your standard US bra size from our bra size calculator.
- Try on a bra from the target brand in that size. Pay attention to how the band and cups feel.
- If the band feels too tight on the loosest hook, increase the band offset by +1. If it rides up or feels loose on the tightest hook, decrease it by -1.
- If the cups have spillage (quad-boob), increase the cup offset by +1. If the cups gape or have extra fabric, decrease it by -1.
- Enter these offsets in the table above and save. The converter will now use your personalized offsets whenever you convert sizes involving that brand.
It may take trying 2-3 sizes in a brand to find your perfect offset. Once calibrated, you can confidently order that brand online in your adjusted size.
Frequently Asked Questions
Do I need to calibrate every brand?
No. Most people only calibrate the 3-5 brands they actually buy from. If you leave a brand at its default (0 offset for both band and cup), the converter uses the brand's standard system conversion. Calibration is most useful for brands where you know from experience that their sizing runs differently from the standard.
Does calibration apply across all bra styles from the same brand?
Not always. Some brands use different sizing for different collections (e.g., their sports bras vs. their everyday bras). The calibration tool uses a single global offset per brand. If a brand has significant style-to-style variation, you may need to adjust mentally based on the specific bra style. Reading customer reviews that mention fit is always helpful.
How often should I update my calibrations?
Re-evaluate your calibrations whenever your body changes (weight fluctuation, pregnancy, nursing, menopause) or when you notice a brand has updated their sizing. Most users find their calibrations remain accurate for 6-12 months. You can also check by re-measuring yourself with our calculator every few months.
Can I share my calibrations with others?
Calibrations are stored locally in your browser and are specific to your body and fit preferences. What works for you may not work for someone else. However, you can use the "offset" values when discussing fit in online communities — for example, sharing that a brand runs a cup size small based on your experience.
Don't Know Your Base Size?
Use our free calculator first to get your starting size, then fine-tune per-brand from there.
Try the Bra Size Calculator