The numbers are in for Facebook's acquisition of mobile-messaging application WhatsApp: The social network paid US$22 billion for a startup that generated US$10.2 million in revenue last year. In a regulatory filing on Tuesday, Facebook disclosed WhatsApp's financial results for 2012 and 2013. The messaging service, which reached 400 million active users in December, generated less than 3 US cents in revenue for each one last year. By comparison, Facebook paid US$55 per user when it acquired the company. WhatsApp's net loss was US$138.1 million for 2013. The valuation of the deal was already regarded as lofty, at 19 times projected sales. Still, the results illustrate how far Facebook has to go to get its money's worth for the app, which gets revenue by charging 99 US cents for subscriptions after a user's first year. Chief executive Mark Zuckerberg said he was in no rush to make money from WhatsApp, or Facebook's other growing applications, until they reach one billion users. "The right strategy is to focus on connecting the people before aggressively turning them into businesses," he said on a conference call to discuss Facebook's third-quarter earnings. "Once we get to that scale, then we think they will start to become meaningful businesses in their own right." WhatsApp's growth is going in the right direction - sales more than doubled last year from US$3.82 million in 2012. Its loss widened from US$54.7 million, the filing showed. The app now has more than half a billion users. Facebook already had a product for chatting, Messenger, when it acquired WhatsApp. Zuckerberg said that the use case for Facebook's Messenger is different than for WhatsApp. People use Messenger to communicate with their Facebook friends, while WhatsApp is more of a text-messaging replacement that people might use with those who are not their friends on social media. The two products are seeing growth in some of the same countries, he said.