There’s no scientific formula to determine how an author’s online following relates to the number of books sold. So we ran several social media celebs turned authors through a thoroughly unscientific Social Media Book Power Meter that takes into account a book’s print unit sales and weeks on sale, and its author’s social following. Does a high rating reflect a months-long bestseller—or an author who’s still building an audience? Might a low rating translate to modest book sales—or an astronomical number of followers, or just a book that’s been around awhile? Yes, yes, yes, yes, and yes.

Justin Halpern, Sh*t My Dad Says (Morrow/Dey Street)
Halpern continued tweeting his father’s witticisms from @shitmydadsays for several years after the book’s publication in 2010; the last tweet was in June 2014.
Print unit sales: 677K
Twitter followers: 2.9 million
Weeks on sale: 299
SMBPM Rating: 70

Brandon Stanton, Humans of New York (St. Martin’s)
Stanton’s photos of and interviews with the city’s denizens have spawned two adult and one children’s book.
Print unit sales: 453K
Facebook likes: 16.8 million
Weeks on sale: 119
SMBPM Rating: 20

Michelle Phan, Make Up (Harmony)
This book grew out of Phan’s maquillage tutorials, the first of which she posted in May 2007.
Print unit sales: 36K
YouTube subscribers: 8.3 million
Weeks on sale: 66
SMBPM Rating: 7

Josh Sundquist, We Should Hang Out Sometime (Little, Brown BYR)
A memoir by Sundquist, a Paralympic skier who posts motivational videos. His debut YA novel, Love and First Sight, pubs in 2017.
Print unit sales: 33K
YouTube subscribers: 211K
Weeks on sale: 57
SMBPM Rating: 270

Connor Franta, A Work in Progress (Atria/Kewords)
Franta’s memoir, like his videos, covers issues of body image, identity, and sexuality.
Print unit sales: 196K
YouTube subscribers: 5.3 million
Weeks on sale: 40
SMBPM Rating: 90

Mamrie Hart, You Deserve a Drink (Plume)
A cocktail recipe accompanies each chapter of the boozy comedian’s memoir.
Print unit sales: 26.5K
YouTube subscribers: 1.2 million
Weeks on sale: 35
SMBPM Rating: 78

Zach Klein, Cabin Porn (Little, Brown)
The book version of Klein’s Tumblr collection of rustic homes was the second-most popular House & Home title of 2015, per Nielsen BookScan.
Print unit sales: 27.6K
Tumblr followers: 350K* (reported by publisher)
Weeks on sale: 17
SMBPM Rating: 460

PewDiePie, This Book Loves You (Razorbill)
The Swedish vlogger who films himself playing video games made mainstream headlines when he sold this book of tongue-in-cheek affirmations.
Print unit sales: 87.7K
YouTube subscribers: 41.8 million
Weeks on sale: 14
SMBPM Rating: 15

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