Apple has sold over half a billion iPhones since the device first launched in 2007, according to a new report.
Sales figures gathered by Forbes, however, suggest that the 500 millionth iPhone was sold somewhere on earth within the last few weeks.
Putting an exact date on the half-billionth iPhone is difficult without official figures from Apple, but estimates taken from Morgan Stanley analysts would place the date as 8 March.
Exponential sales growth
Having launched the first iPhone in 2007, it took Apple almost four years to reach the 100 million sales mark. Since then, however, iPhone sales have increased exponentially to the point that it has only taken around eight months to achieve the last 100 million sales.
With the expected launch of the iPhone 6 later this year, sales of the smartphone are forecast to increase once more as users rush to upgrade to the latest model.
Rumours have so far hinted at a thinner device with a larger screen and more powerful Apple A8 processor.
One billion iPhones by 2016
A recent move by Apple to re-launch the iPhone 4 in emerging markets could allow the California-based company to compete better against cheaper Android smartphones.
Taking these events into account with current sales trends, the Forbes report estimates suggest the 600 millionth iPhone sale will take place soon after the launch of the iPhone 6 - expected in the autumn - with the one billion mark hit by the end of 2016.