CITEworld wrote about Microsoft losing $1.7 billion on Surface so far.

total loss for FY2014 was then $680 million ($2.192 in revenue minus $2.872 in cost of that revenue).

But that was small potatoes compared to what Microsoft lost on the Surface the previous fiscal year. Using Microsoft’s stated revenue of $853 million and some arithmetic to backtrack to the FY2013 cost of revenue, Computerworld concluded that the cost of revenue for the 12 months starting July 1, 2012, was $1.902 billion.

The total loss for FY2013 was thus $1.049 billion ($853 million minus $1.902 billion in cost of revenue and adjustments).

Since Microsoft started selling the Surface nearly two years ago, it has lost $1.7 billion on the line. (Microsoft, SEC filings.)