Measure your bra size in three steps. One: band size, directly under the bust, snug but not tight. Two: bust size, horizontally across the fullest point, without compression. Three: work out your cup by subtracting band size from bust size. 12 cm = B, 14 = C, 16 = D, 18 = E, 20 = F. Measure preferably in the late afternoon, when breasts are at their normal volume.
Why 70-80% of women wear the wrong bra size
This isn't a marketing figure. It's the result of independent fit studies, including one from the University of Portsmouth (2019) and internal analyses by major lingerie brands. The cause comes down to three structural problems:
- Your own size keeps changing — pregnancy, weight changes, hormonal shifts and age all affect both band size and cup.
- Size charts differ per brand — a 75B at brand X can be a 75C at brand Y.
- Most measuring instructions aren't read in full — many women measure only the band and guess the cup.
The three steps — explained in detail
Step 1 — Measuring the band
Stand up straight, arms relaxed by your sides. Place the measuring tape directly under your bust, where the band of the bra should sit. The tape should fit snugly — tight enough that you can just slide two fingers underneath it, no more.
Round your result to the nearest 5:
- 63–67 cm = band size 65
- 68–72 cm = band size 70
- 73–77 cm = band size 75
- 78–82 cm = band size 80
- 83–87 cm = band size 85
- 88–92 cm = band size 90
- 93–97 cm = band size 95
Step 2 — Measuring the bust
Wear a thin, unpadded bra — no push-up. Place the measuring tape across the fullest point of your bust (usually at nipple height). It should lie horizontally, not shifting up or down at the back.
Important: the measuring tape shouldn't press into the bust. Just pull it taut so it lies against the skin, without changing its shape.
Step 3 — Working out the cup
Subtract the band size from the bust size. The difference determines your cup:
- 10 cm difference = cup A
- 12 cm = cup B
- 14 cm = cup C
- 16 cm = cup D
- 18 cm = cup E (sometimes DD in the Netherlands)
- 20 cm = cup F
- 22 cm = cup G
- 24 cm = cup H
Example: underbust 78, overbust 94 → 78 rounds up to 80, difference 16 cm = cup D. Your size is 80D.
Would you like the full cup size chart from AA to J, including sister sizes? Then check out our cup size chart.
The 8 most common measuring mistakes
- Measuring with a padded bra — leads to a cup result that's too small. Always measure with a thin bra or without one.
- Measuring tape too tight around the overbust — compresses the breast, resulting in a cup that's too small.
- Measuring tape too loose around the underbust — leads to a band size that's too large.
- Measuring in the morning — breasts are slightly larger in the evening due to fluid retention. Measure consistently in the late afternoon.
- Measuring in the mirror — the mirrored perspective distorts the result. Better: ask someone else to help or take a photo.
- Guessing your cup size — even after years of going "by feel", you're often 1-2 cups off.
- Measuring at the low point of your cycle — the breast is smaller then. Measure on day 10-14.
- Reading the band size from old bras — measure your body, not your closet.
The five signs of a well-fitting bra
- The underbust band sits horizontally, below the shoulder blades.
- You can fit two fingers between the band and your body — no more.
- The cups are fully filled, without overflow and without wrinkles.
- The shoulder straps don't dig in, but don't hang loose either.
- The center gore (between the cups) lies flat against the breastbone.
Want to check each of these five points one by one against the bra you're wearing now, including the seven signs of the wrong size and the solution for each sign? Then use the 5-point check: how should a bra fit.
When to measure again?
- After pregnancy and breastfeeding — cup and band size can change by 2-3 steps.
- After a weight change of +/- 3 kg.
- After an athletic transformation.
- During perimenopause / menopause.
- Every two years as a precaution.
What to do if your size still doesn't fit with us
At Novyre we offer 14 days returns, even after brief try-on moments. Exchange for free for the right size, or get your money back. Our fit advisors answer fit-related questions by email (info@novyre.nl) usually within 24 hours.
View Luma Forma 2.0 in 13 sizes →
Frequently asked questions
How precisely should I measure my underbust?
Accurate to the centimeter. A difference of 2 cm is enough to lead to the wrong band size. Measure twice and take the average.
My breasts aren't the same size — which side do I measure?
Measure both and use the larger side as your basis. Slight asymmetry of up to 1 cup is completely normal.
How do I know if the cup is too small?
Three signs: cup edge overflow, a center gore that lifts away from your breastbone, or a visible line under a fitted T-shirt.
How do I know if the band is too big?
The band rides up when you raise your arms. Or you can fit more than 2 fingers behind the band.
How often should I measure again?
At least once a year, plus after any noticeable change in your body.
I'm a G cup — does the difference rule still apply?
Yes, the linear rule works up to cup H. From cup H onward, the fit becomes more specialized — professional advice is recommended at that point.
