How A NASA Scientist Helped Size My Bra

An app called ThirdLove promises to calculate a woman’s bra size using just two tank top-clad iPhone selfies and a bit of technology developed under the supervision of a NASA scientist.


In most contexts, if someone asked me to take a photo of my bust using their iPhone app, I would say no.


But ThirdLove, a retail startup that promises to calculate a woman’s bra size using just two tank top-clad iPhone selfies, has all the signs of a legitimate business: Its cofounder, Dave Spector, is a former partner at Sequoia Capital (he started the company with his equally qualified wife, Heidi Zak). They’ve raised $5.6 million from investors whose names I recognize. And a NASA scientist heads up the engineering team.

So unless this is an overly elaborate plan to relaunch the creepshots subreddit, I figure it’s safe.

The current version of the ThirdLove app (it’s still in private beta) features a tutorial in the voice of a polite but firm woman who sounds a bit like my grade school principal. As instructed, I stand in front of my mirror with my phone at my belly button. “Slightly raise right end of the phone,” she says. Then “slightly raise left end of the phone.” Then, “slightly raise right end of the phone.” After about 50 more rounds of this, there’s a gratifying “Good job” and a countdown to the photo.

Instructions on the screen ask me to line up a box with the iPhone in the photo and to place a line on my chest. Then the principal voice walks me through the same process for a photo from the sideways perspective.

This is where the technology, about which Spector would “prefer not to get into too much detail,” comes in. Ara Nefian, a senior scientist with the Intelligent Robotics Group at NASA Ames Research Center, led the team that developed it. His explanation isn’t much more specific. He says the back end “involves several methods of advanced computer vision, body modeling, and machine learning” and uses the iPhone in each photo as a “calibration object” for estimating the parameters of the camera. Once those parameters are known, it’s possible to accurately measure a 3-D object—in this case, the human body—using a 2-D image.

The result from the user’s perspective is a customized store filled with ThirdLove products in her size. What is that size? It doesn’t say. The presumption is just that everything fits. I won’t find out whether that’s actually the case until I receive the bra in the mail. (Update: It fits)


ThirdLove eventually plans to expand its product line to other types of clothing. Spector says that as more commerce moves to mobile, sizing is a point where a brand can stand out. “If you go into a Hollister store, it’s like you’re at the beach. There are beautiful models walking around. There’s a livestream of the beach in California,” he says. “It’s pretty hard to beat that when you’re working with a flat, two-dimensional 12-inch screen or a smartphone.”

Perhaps because bra fitting is a particularly unpleasant experience (for the unacquainted: cold room, full-length mirror, stranger wrapping you in measuring tape), there are several startups targeting the category with alternative sizing techniques. A startup called True&Co, for instance, uses a quiz to help women shop. Another called Brayola sizes bras by asking women questions about the bras they already have.

ThirdLove is the only solution I can find, however, that employs a team of computer-vision PhDs. It seems a bit like tech overkill for what is a fundamentally an analog problem, but if that’s what it takes, so be it.

Update: A Communications executive at the NASA Ames Research Center reached out to reiterate that Ara Nefian is a contracted researcher and that “No NASA software, technology, equipment or facilities were used in Mr. Nefian’s consulting to Third Love.”

[Bra Image: Olga Drabovich via Shutterstock | Flickr user NASA]

About the author

Sarah Kessler is a senior writer at Fast Company, where she writes about the on-demand/gig/sharing "economies" and the future of work.