Quick answer
To measure for a plunge bra, you need two numbers: your band size (measured snugly under your bust) and your bust size (measured at the fullest part). Subtract the band from the bust to find your cup size. Always remeasure before buying, especially if your weight has changed or you're switching brands.
Why Plunge Bras Need a Different Fit Approach
Plunge bras have a deep V neckline and often use non-padded, mesh-lined cups that rely on precise fit for support. Because the center gore sits lower, the band does more of the work. A loose band or wrong cup depth can cause gapping, slipping straps, or underwire digging. That's why measuring specifically for a plunge style matters more than using generic bra sizing.
What You'll Need to Measure
Grab a soft measuring tape, a non-padded bra (or no bra), and a mirror. Wear the bra you plan to measure over, or go braless for the most accurate bust measurement. Write down both numbers in inches or centimeters and keep them consistent.
Common Plunge Bra Fit Issues and How to Avoid Them
The most common mistake is choosing a band that is too large to compensate for a small cup. Plunge bras with stretch lace, like the Clara White Silk & Lace Plunge Bra, can mask a poor fit because the lace stretches. Always check that the band stays level across your back and that the underwire sits flat against your sternum without floating or digging.
How to Measure for a Plunge Bra: Step by Step
- Measure your band size: Wrap the measuring tape snugly around your ribcage, directly under your bust. Keep the tape level and parallel to the floor. Breathe out and take the measurement in inches. If the number is even, add 4 inches; if odd, add 5 inches. This is your band size. Common mistake: pulling the tape too tight. The band should be snug but not digging in—you should be able to slide two fingers under it.
- Measure your bust size: Stand straight and wrap the tape around the fullest part of your bust, usually across the nipple line. Keep the tape loose enough to rest against your skin without compressing the breast tissue. Round to the nearest whole number. Common mistake: measuring over a padded bra. Measure over a non-padded bra or go braless for the most accurate bust measurement.
- Calculate your cup size: Subtract your band size from your bust measurement. Each inch of difference equals one cup size: 1 inch = A, 2 inches = B, 3 inches = C, and so on. For example, if your band is 34 and bust is 36, you're a 34B. Common mistake: assuming cup size is absolute. A 34B is smaller in volume than a 36B because the band is different. Always use your band measurement first.
- Check the fit with a plunge bra: Put on a plunge bra like the Clara White Silk & Lace Plunge Bra. The center gore should lie flat against your sternum. The underwire should follow your breast root without poking. The band should stay level across your back and not ride up when you raise your arms. Common mistake: ignoring the gore. If it floats away from your chest, the cup is too small or the band is too large. Try a different size.
- Adjust straps and closure: Shorten the straps so they sit comfortably on your shoulders without digging in. The back closure should be on the loosest hook when new—you'll tighten it as the band stretches over time. Adjustable straps with gold rings and sliders, like those on the Camilla Navy Silk & Lace Plunge Bra, let you fine-tune the fit. Common mistake: relying on straps for support. The band should carry about 80% of the weight. If your straps are digging in, your band is likely too loose.
Plunge Bras That Fit Well
- Clara White Silk & Lace Plunge Bra: This beautiful underwired bra is handcrafted from white floral stretch lace and classic white silk. It features a 100% silk band and mesh-lined cups composed of 67% recycled polyamide, 16% viscose, and 17% elastane, all certified by Oeko-Tex Standard 100. The plunge style includes non-padded cups and adjustable straps adorned with gold-coloured rings and sliders. The stretch lace and mesh-lined cups adapt to your shape, but the band must be snug for the underwire to stay flat. If your band measurement is off, the silk band won't provide enough support.
- Camilla Navy Silk & Lace Plunge Bra: This underwire bra is artfully crafted from navy oeko-tex stretch lace and 100% silk. Its plunge design features non-padded cups with adjustable straps and gold rings and sliders. The back fastens with a black hook and eye closure with gold detailing. The adjustable straps and hook-and-eye closure let you fine-tune the fit, but the cup depth is fixed. Measure your bust at the fullest point to ensure the non-padded cups don't gap or compress.
