Knix vs Spanx Bra Size Comparison
Wondering how Knix and Spanx bra sizes compare? Both brands use standard US bra sizing, so a 34C should be the same measured size in either brand. But fit, size range, and style vary — here's a detailed breakdown to help you find your perfect size in both.
Knix runs true to size.
Spanx runs small — consider sizing up.
Size Chart: Knix vs Spanx
Common bra sizes compared across US, UK, and EU systems for both brands.
| US Size | Knix UK | Knix EU | Spanx UK | Spanx EU | Bust (cm) |
|---|---|---|---|---|---|
| 32B | 32B | 70B | 32B | 70B | 85 |
| 34B | 34B | 75B | 34B | 75B | 90 |
| 34C | 34C | 75C | 34C | 75C | 93 |
| 34D | 34D | 75D | 34D | 75D | 95 |
| 36C | 36C | 80C | 36C | 80C | 98 |
| 36D | 36D | 80D | 36D | 80D | 100 |
| 38DD | 38DD | 85E | 38DD | 85E | 108 |
Both brands use standard US bra sizing. UK and EU equivalents follow the same conversion.
How Knix and Spanx Fit Differently
Knix runs true to size, while Spanx tends to run small. If you're switching between these brands, you may want to adjust your size — size up when buying Spanx.
Knix Fit
Knix bras run true to size. The WingWoman Contour Bra uses standard band-and-cup sizing (bands 28–48, cups A–H), while most wireless and everyday styles use Knix's own alpha-plus scale (XS through XXXXL++) found via their on-site size guide. Because the bras are wireless, the band feels snug for the first few wears and washes, then relaxes — don't size up on day one.
Spanx Fit
Spanx bras tend to run slightly small in the band due to their compression-focused design. Size up in the band if you prefer a less snug fit. Cup sizes are true to size. Their wireless styles are more relaxed than underwire.
Does Knix or Spanx Run Bigger?
Knix runs bigger than Spanx. Since Spanx tends to run small, you may need to size up when buying Spanx or size down when switching to Knix. Start with your measured size in Knix and consider going up half a size in Spanx.
Which Brand Is Right for You?
Choose Knix if you want:
- ✓ Comfortable everyday wear
- ✓ Consistent, true-to-size fit
Choose Spanx if you want:
- ✓ Comfortable everyday wear
- ✓ Snug, compression-style fit
Not sure of your size?
Use our bra size calculator to find your size in Knix, Spanx, and 12 other brands — all from your measurements.
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