Which smartphone series is the best-selling of all time?

The iPhone 6 and iPhone 6 Plus form the best-selling smartphone series of all time. Apple introduced both models in September 2014, expanding the iPhone lineup with larger displays and a new, thinner design.

The iPhone 6 had a 4.7-inch screen, while the iPhone 6 Plus used a 5.5-inch display. Their larger sizes addressed a major trend in the smartphone market and helped Apple compete more directly with large Android phones. Both models used Apple’s 64-bit A8 chip and introduced Apple Pay support through NFC.

Demand was enormous: Apple reported more than four million combined pre-orders in the first 24 hours and ten million sales during the first three days. Estimates published later placed combined lifetime sales of the iPhone 6 and 6 Plus at roughly 222 million units, ahead of other individual smartphone models.

The iPhone 6S generation followed in 2015, but it is not the same series for this question. Another common confusion is naming the iPhone 5, which was highly successful but did not surpass the iPhone 6 family’s sales.