How can I determine whether a Steam game can be activated on Origin as well?

As described by title, I own a certain number of games on Steam. How can I determine whether a Steam game can be activated on Origin as well?

Solution 1:

This list was obtained here. In addition, the following Steam games also can be activated on Origin:

+---------------------------------------+-------------------+
|              Game Title               | Can be activated? |
+---------------------------------------+-------------------+
| Command & Conquer - Red Alert 3       | Yes               |
| Dragon Age:Origins - Ultimate Edition | Yes               |
+---------------------------------------+-------------------+

If you have an EA Game not listed here that you can retrieve the CD Key from Steam you can try to activate it on Origin and even if it doesn't work, you may be able to contact support and get them to activate it.

Solution 2:

There is now an official list of redeemable games on Origin Code Redemption FAQ. This is the up-to-date list of games accepted:

Can I add an EA game that I purchased outside of Origin to my Origin Game Library? Currently all EA games released in 2009 or later can be added to your Origin Game Library. We’re working to enable this option for EA’s older titles as well. At this point, all of the following titles are enabled for this feature:

Alice 2: Madness Returns
Battlefield 3
Burnout Paradise
Command & Conquer 4: Tiberium Twilight
Command & Conquer: Red Alert 3
Command & Conquer: Red Alert 3: Uprising
EA Create
Crysis 2
Darkspore
Dead Space
Dead Space 2
Dragon Age: Origins
Dragon Age: Origins Awakening
Dragon Age 2
FIFA Manager 09
FIFA Manager 10
FIFA Manager 11
FIFA Manager 12
FIFA Soccer 09
FIFA Soccer 10
FIFA Soccer 11
FIFA Soccer 12
Gattling Gears
Harry Potter and the Deathly Hallows Part 1 
Harry Potter and the Deathly Hallows Part 2
Harry Potter and the Half Blood Prince
Kingdoms of Amalur: Reckoning (Non-Steam)
Mass Effect 2
Mass Effect 3
Medal of Honor
Mirror's Edge
MySims 
Need For Speed: Hot Pursuit
Need For Speed: Shift
Need For Speed: The Run
Need For Speed: Undercover
NHL 09
Shank
Shift 2 Unleashed
SimCity 4 Deluxe Edition 
The Lord Of The Rings: Conquest
The Saboteur
The Sims Medieval
The Sims Medieval Pirates and Nobles