Apple's iPhone 6 and its big brother the iPhone 6+ are the bestselling iPhone models of all time, with the iPhone 6 coming out ahead by approximately one-third. These iPhone models have broken sales records since their introduction in early November 2014, giving competitors another reason to work harder for smartphone supremacy.

Barely three months after its release, the iPhone 6 generated 71.5 million unit sales, far outpacing its predecessor, the iPhone 5S, by 30%. The larger iPhone 6+ now accounts for 40% of all tablet-style smartphone sales and is the second-bestselling iPhone of all time. Although the Cupertino, CA-based company tends not to break down iPhone sales figures by particular models, it's estimated that as of June 2017, roughly 222.4 units of this generation have been sold. That compares with around 78.3 million units of its successor, the iPhone 7 and 7+, to date.

Released in 2013, the iPhone 5 accounted for 70 million unit sales, and the iPhone 5S recorded 52 million unit sales. These were Apple's top sellers until the 2014 release of the faster iPhone 6 and the larger Phone 6+. Revenue estimates for the iPhone 6 is set between $65.2 and $68 billion dollars, surpassing iPhone 5 revenues of $45.6 billion.

This leaves little doubt to iPhone sales being the biggest money maker for Apple. With sales still burgeoning and another year to go before the next iPhone release, the iPhone 6 is sure to remain the top seller for quite some time, though the strong showing of the iPhone X – advance orders of which sold out in November 2017, even before its release – may finally topple it.

Overall, iPhone sales rose 3% (over last year) to 46.67 million in the fourth fiscal quarter ended Sept. 30, 2017, generating revenues of $28.8 billion for Apple.

To learn more, check out The Cost of Making an iPhone.