Just how popular is the Apple Watch?

Apple has been quiet on the number of Apple Watch units it has sold so far, but that’s not stopping analysts from estimating.

Canalys says that Apple has become the ‘world’s leading vendor of wearable bands’ in Q2 2015, according to its estimates.

It reckons the watch has reached 4.2 million shipments, overtaking rivals Fitbit, Xiaomi and other smartwatch vendors, despite Apple’s product having a higher price tag. Analyst Stifel, on the other hand, believes Apple has sold 3.3 million watches.

However, Canalys says that early sales were hindered, due to two factors. Firstly, because Apple missed the Q4 2014 holiday season and secondly, because supply constraints stalled shipments for the first couple months after launch.

"The Apple Watch is the most sophisticated smartwatch to date, and it has proved popular with Apple fans worldwide," said Chris Jones, VP and Principal Analyst at Canalys.

"But Apple and other vendors still face important challenges to make the smart watch a breakout hit. Improvements in performance, battery life and sensor integration are needed to make future models more attractive, but it is the quality of third-party apps that will determine whether the Apple Watch will be a long-term success."

Forbes reports that Apple will still be reluctant to share numbers when its next financial report is published. The tech giant is expected to push its Apple Watch sales into the ‘other products’ category, along with Beats headphones, Apple TV and accessories, making it difficult to find out just how well Apple Watch sold.

Last quarter Apple posted $1.7 billion in revenue in that category.

Some say Apple are keeping cards close to its chest as it doesn’t want to share details with its competitors, while others suggest the company doesn’t want everyone to know how poorly it has sold.

Research firm Slice Intelligence says that orders for the Apple Watch dropped 90 per cent since the device’s launch.