Breast implant upgrade. Will 100cc be a noticeable difference?

A general rule is that a 75 cc difference between sides is noticeable. The other factors that will affect how noticeable the difference is are the change in projection and fullness. Increasing the projection (low, moderate, full, extra full), rather than the base diameter of the implant will translate to a more noticeable difference.

As a rule, you should change by at least 100 cc whether going larger or smaller. This of course depends on a lot of variables including breast volume, implant profile & size, and height & weight.

Dear cyndspan,
breast implant type and sizing selection is a complicated process and requires a detailed consultation that includes a discussion of your goals, a detailed examination, and a lengthy discussion. But the decision will always start and end with the patient. When it comes to sizing, we have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements.Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If it is too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match.Of all of my breast augmentation patients, every one of them has been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small.You should discuss your concerns with a board-certified plastic surgeon and make sure that your surgeon understands your goals.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

You have to decide if this increase is "worth it" to you. Going up 100 cc's will place you in the next cup size.

Going from a 255cc to a 350cc implant will be a large difference in size. Generally speaking, it will be one cup size bigger (possibly even a bit more).
A 50cc increase is noticeable especially when dealing with smaller implants to start with.