When will tablets outsell traditional PCs?

I truly believe, and many others in the company believe, that there will come a day that the tablet market in units is larger than the PC market.

Tim Cook Discusses Q1 2012 Results – Earnings Call Transcript – Seeking Alpha

Question is when?

I began by projecting growth rates of various market participants including the leading Windows PC makers (HP, Acer, Dell, Lenovo and Asus), the combined “others” and the Mac. I also added the iPad, Samsung’s tablets, other Google sanctioned Android tablets and Amazon. I also projected a split between traditional and tablet Windows shipments.

The underlying assumptions are:

1. Mac growth continues at 25% as it has on average for a few years
2. Windows grows slightly in 2012 with the introduction of Windows 8 late in the year. However I anticipate Windows 8, including tablet versions, to mostly be upgrades with slow enterprise take-up within this time frame.
3. The tablet versions of Windows begin shipping in Q4 2012 with 7% of total Windows shipped. The ratio reaches 20% by end of 2013.
4. iPad growth will flatten for ’12 and ’13 at 100%, similar to iPhone’s historic performance.
5. Android tablet growth will be significant in the current year and follow iPad growth pattern though settling at 80% during ’13.
6. Amazon growth will be approximately 80%.

Building the platforms combined growth bottom-up gives the following forecast for the next two years (and historic growth shown for perspective.)

[FF = form factor]

Given these assumptions, the day when the tablet market (by units) will exceed that of traditional PCs will come sometime in the fall of 2013.

As yesterday’s post noted, the tablet market will be additive. This can be seen in the vendor shipments forecast that accompanies the model: