100 cm Underbust Bra Size
A snug 100 cm underbust (≈ 39.4″) is a US 40 band, labelled EU 90 and FR 105. Slide to your bust in cm for the cup.
My underbust is 100 cm: what's my size?
Why the EU label isn't your centimeters. An 84 cm underbust is a US 34 band, which the EU labels 75: the label follows US × 2.5 − 10, not the raw reading. That is why a converted size can feel a step off from a bra drafted natively in EU sizing.
Every size on a 40 band, by bust in cm
| Bust | Difference | US size | EU · FR · UK |
|---|---|---|---|
| 104 cm · 41″ | 1″ | 40A | 90A · 105A · 40A |
| 107 cm · 42″ | 2″ | 40B | 90B · 105B · 40B |
| 109 cm · 43″ | 3″ | 40C | 90C · 105C · 40C |
| 112 cm · 44″ | 4″ | 40D | 90D · 105D · 40D |
| 114 cm · 45″ | 5″ | 40DD | 90E · 105E · 40DD |
| 117 cm · 46″ | 6″ | 40DDD | 90F · 105F · 40E |
| 119 cm · 47″ | 7″ | 40G | 90G · 105G · 40F |
| 122 cm · 48″ | 8″ | 40H | 90H · 105H · 40FF |
100 cm underbust: answered
What bra band is a 100 cm underbust?
US 40. EU 90, FR 105, AU 18, IT 6. 100 cm is about 39.4 inches, rounded to the nearest even band.
Why is a 100 cm underbust not an EU 100 band?
EU labels follow the US band (× 2.5 − 10) rather than raw centimeters; a 100 cm reading is US 40 → EU 90. Brands drafted natively in EU sizing may grade from centimeters and land one band different: the sister size settles it.
How many cm is one cup?
About 2.5 cm of difference between bust and underbust.
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