Every great fit starts with accurate measurements. Here’s how to find your best fit with our bras: 

  1. What you wear matters! Start with a non-padded or lightly padded bra, or go full birthday suit if you’re alone. The best fit is found when you don’t add a lot of extra bulk or compression to your measurements. 
  2. Measure Your Underbust: Wrap a measuring tape snug, but not tight, around your ribcage, right under your bust. Ensure the tape is straight and level around your body. This measurement, in inches, is your band size. If you get an odd number, round up to the next even number for the best fit.
  3. Band Size Variation for Comfort: Take a deep inhale before you measure to expand your ribcage to the largest it might be, and you’ll get a more comfy-fitting band size.


  1. Measure Your Full Bust: Now, measure around the fullest part of your bust, keeping the tape level but not too tight. This measurement gives you your bust size, crucial for determining your cup .
  2. Determine Your Cup Size: Take your full bust measurement and subtract your underbust measurement. This tells you the cup size. Each inch of difference represents one full cup size. For example, a 1" difference = A cup, a 2" difference = B cup, and a 3" difference = C cup, etc.

At iteration, we use alpha-sized bras with a fuller bust option, as our garments have been created to be very fit-flexible. To find your size in our bras, you'll need to take both measurements you've found, consult the size chart below, and find where your two measurements intersect.

Bra size chart in Inches

Find your iteration size: using the size chart below, find where you fit in terms of band size by using the left two columns. Use the top two columns for where your cups fall. Where your underbust size row meets your cup size column is your recommended size.
FULL BUST - UNDERBUST = 1" 2" 3" 4" 5" 6" 7"
26.5" - 28.5" 28 XS XS XS XS XS+ XS+ XS+
28.5" - 30.5" 30 XS XS S S S+ S+ S+
30.5" - 32.5" 32 S S S S S+ M+ M+
32.5" - 34.5" 34 M M M M M+ M+ M+
34.5" - 36.5" 36 M M L L L+ L+ L+
36.5" - 38.5" 38 L L L L L+ XL+ XL+
38.5" - 40.5" 40 XL XL XL XL XL+ XL+ XL+
40.5" - 42.5" 42 1X 1X 1X 1X 1X+ 1X+ 1X+
42.5" - 44.5" 44 2X 2X 2X 2X 2X+ 2X+ 2X+
44.5" - 46.5" 46 3X 3X 3X 3X 3X+ 3X+ 3X+
NOTE: Our fabric is really stretchy and two sizes may work for you. If you fall between D + DD, scroll down for more info on how to best decide your fit.
Standard size options are best suited for cups A through D.
Fuller Bust size options are best suited for cup sizes DD through G.
Fuller Bust sizes are indicated with a + at the end of the size, [i.e. 1X+] Fuller Bust sizes feature a band that is 1" smaller than the band of the same size bra in the Standard Size. They have slightly taller side seams, center fronts and deeper cup molding to accomodate extra breast tissue.

Additional Size Info

At iteration, we offer two options to ensure you find the perfect fit: Standard and Fuller Cup. Here's how to determine which option might be best for you:

Standard Sizes

  • Size Range // XS through 3X 
  • Suitable For // Cup sizes A through D
  • Band Sizing // Fits band sizes 28" to 46"; band length adjusts 2" for each size up or down
  • Details // Designed to provide a comfortable and supportive fit for various body types; best suited for smaller to mid size busts.

Fuller Bust Sizes

  • Size Range // XS+ through 3X+
  • Suitable For // Cup sizes DD through G
  • Band Sizing // Fits band sizes 28" to 46"; Fuller Cup bands are 1" smaller than their Standard sisters for added support; band length adjusts 2" for each size up or down.
  • Details // Slightly taller side seams, center fronts, and deeper cup molding offer additional support and coverage.

Unsure between Standard or Fuller Cup?

If you're between a D and DD cup and unsure which size to choose, consider how you prioritize comfort and support:

  • More Support // Choose the Fuller Cup (+) size for a snugger fit, extra lift, and cup room. If you are full on top, you may prefer this option to avoid a digging neckline.
  • More Comfort // Choose the Standard size for a more relaxed band fit. 
  • Ultra Comfort // If you prefer even more comfort and similar cup coverage to the Fuller Cup, consider sizing up to the next size up in the standard range.

For example, if your underbust measures 32" and your fullest bust is 37", we would typically recommend a size S+. However, if you prefer a slightly more relaxed fit, a Standard Small might be the better choice, offering an extra inch in circumference for added comfort. You might consider a size Medium if you like a very comfortable fit around the band and additional cup coverage.

Triangle Bra

Just beyond basic, our Triangle Bra is a fashion essential that hugs in all the right places while being versatile enough to pair with your favorite blouse, tee, or racerback top.

  • Neckline // Hits just above your fullest part without being too covering.
  • Underbust // Soft, wide, fabric-covered elastic that doesn't dig in with a keyhole feature for the perfect peek of skin.
  • Straps // Matte, wide elastic that stays put with front adjusting sliders. Slightly closer set than the Scoop, so it works for sloped shoulders.
  • Multi-Wear Option // Made just for you comfort; adjustable j-hook slide ups and down to convert to a racer back in a flash or snap back to straight straps.
  • Why Choose This // For a morning to night look that goes with everything and feels feminine. You want to feel chic, stylish, and a pinch of sexy while being fully contained.

Plunge Bra

Dive into elegance with our iconic Plunge Bra, tailored to perfectly complement your favorite V-neck outfits. The Plunge Bra features our lowest neckline, an ideal choice for adding a touch of spice beneath any top or blouse.

  • Neckline // A daring, low-cut design enhances your silhouette and ensures a secure fit.
  • Underbust // Prioritize comfort with a wide, soft, fabric-covered elastic band that prevents digging.
  • Straps // Wider fabric shoulder straps with adjustable, reduced-stretch back straps stay put for all-day support.
  • Multi-Wear Option // Easily switch from a traditional to a halter-style racer-back with the convenient j-hook, adapting to any outfit.
  • Why Choose This // It’s more than a bra—it’s a style statement. Whether for a night out or a day at the office, The Plunge offers a sleek look and unmatched comfort, making it your essential go-to bra.

Scoop Bra

Just beyond basic, our Triangle Bra is a fashion essential that hugs in all the right places while being versatile enough to pair with your favorite blouse, tee, or racerback top.

  • Neckline // Rounded square neck scoop, this is our highest neckline that separates and contains with a touch of sporty.
  • Underbust // Cleverly hidden from outside view with wide, soft, elastic, covered with fabric so it doesn't dig in.
  • Straps // Wider set straps using matte, wide, reduced-stretch elastic that stay put with easy to reach front adjusting sliders.
  • Multi-Wear Option // Let multi-wear comfort meet you where you are; adjustable j-hook at the back can slide up and down and easily convert to a racer back or switch to straight straps in a pinch.
  • Why Choose This // For your everyday grind, wear it when comfort is key and you can't risk falling out. Great for light exercise like yoga or pilates.