375cc vs 400cc Breast Implant Sizers

Drag the slider to compare the same model without sizers and wearing 400cc Oumènta breast augmentation sizers.

External sizing demonstration only. Not a prediction of surgical results.

Choose your Pocket Bra by your current band size:

The Pocket Bra should feel snug and supportive, similar to a sports bra. There's no need to size up for this kit. The internal pockets are designed for the sizers and keep both sizes in the same position, which matters when only 25cc separates them.

Leaning a Little Smaller? Compare our 350cc vs. 375cc 2-Pack or our 325cc vs. 375cc 2-Pack.

Leaning a Little Larger? Compare our 400cc vs. 425cc 2-Pack or our 400cc vs. 450cc 2-Pack.

Want a More Noticeable Difference? Our 350cc vs. 400cc 2-Pack and 375cc vs. 425cc 2-Pack each compare two sizes 50cc apart.

Want a Third Size? Explore our 350cc vs. 400cc vs. 450cc 3-Pack or our 300cc vs. 350cc vs. 400cc 3-Pack, or build a custom kit with 375cc, 400cc, and 425cc. You can also choose any two volumes with our Choose-Any-2 Sizer Kit.

375cc vs. 400cc Breast Implants: How Different Are They?

400cc has 25cc more volume per breast than 375cc. That's about 6.7% more sizer volume, or roughly 1.7 tablespoons per side.

That doesn't mean your breasts will look 6.7% larger. The percentage describes the volume of the sizer, not your overall breast size. How either volume looks on you depends on your existing breast tissue, chest width, and frame, and after surgery also on implant profile and placement.

Why Your Eyes Adjust

When you wear a new size for a while, your sense of "normal" shifts. A size that looked full on day one can look ordinary by day three. That's one reason some women find themselves drawn to bigger and bigger sizes as they try sizers.

This isn't a problem. It's useful information. Sometimes it reveals that you really do prefer more fullness. Other times it's simply your eyes adjusting. The goal is to tell which is happening for you.

How to Test Your Preference

Alternate, don't escalate. Switch back and forth between 375cc and 400cc rather than wearing one size for days and then moving up.

Take a reset day. Spend a full day without sizers. Then try each size again. Notice which one you're happy to see.

Go back to day one. Compare your first photos with each size against photos from later in the week. If you still prefer the same size, that preference is likely real.

Check your reaction to the smaller size. After a reset day, does 375cc look right, or does it still feel like something is missing? Your answer after a break is more reliable than your answer after five days in the larger size.

Bring your photos and notes to your consultation. They help your surgeon understand both what you prefer and how consistent that preference is.

If You Keep Wanting to Go Up

If 400cc still feels right after a reset day, try comparing it with 425cc. If a reset day makes 375cc look like plenty, that's equally valuable. And if both look a bit full after a break, consider comparing 350cc.

For more on this question, read 275cc vs. 375cc: Will You Regret Going Too Big or Too Small?

Will 375cc or 400cc Give Me a D Cup?

There's no reliable conversion between implant volume and cup size. The same volume can look different on two women, and cup sizes vary between bra brands. Oumènta sizers show you external volume under clothing; they can't predict your cup size after surgery.

For more on volume and cup size, read A Cup to C Cup Breast Implants: How Many CCs?

Why Try Sizes Before Surgery?

In a published study of 567 women, a group who tried silicone implant samples in a bra before surgery generally reported that the preoperative sizing process was helpful. The study used implant samples, not Oumènta sizers, and doesn't show that Oumènta products affect surgical outcomes.

Read the published preoperative sizing study.

Explore Individual Breast Augmentation Sizer Sizes

Learn more about our 375cc sizers, 400cc sizers, and 425cc sizers, or try our Breast Implant Size Calculator for a suggested range of sizes to try.

For more about choosing a size, read 350cc vs. 450cc Breast Implants: Which Size Is Right?, What Is At-Home Breast Implant Sizing?, and How to Choose the Right Breast Implant Size, or browse our full Breast Implant Sizing Guide.

How much bigger is 400cc than 375cc?

400cc has 25cc more volume per breast, about 6.7% more than 375cc. The visible difference is usually subtle and most noticeable in fitted clothing and from the side.

Why do larger sizes start to look normal after a few days?

Your eyes adjust to what you see every day. After wearing a size for a while, it can start to feel like your new normal. Alternating sizes and taking a day off from the breast augmentation sizers can help you judge each size more fairly.

Should I get 375cc or 400cc breast implants?

That's a decision for you and your plastic surgeon. Wearing both sizes at home can help you understand which look you prefer. Your surgeon will assess your anatomy and recommend implant dimensions that suit you.

Why buy a 2-Pack instead of a 3-Pack?

If you've already narrowed your choice to 375cc or 400cc, a 2-Pack focuses on just those two sizes, at a lower price. If you're still exploring, a 3-Pack or custom kit adds a third size for a wider comparison.

Will these sizers show me how my implants will look?

No. Oumènta sizers show external volume under clothing. They can't reproduce implant placement, tissue response, implant profile, or surgical results.