I was previously using the Google Goggles app on my Android phone to scan QR codes but turns out that you don’t need a separate QR code reader as the built-in Google Search widget can decode QR codes as well.
To scan a QR code, you need to tap the microphone icon inside the Google Widget and then choose “Search with Camera” option from the menu available in the lower right corner (see the first screenshot).
Now point your mobile camera to any QR Code, tap the on-screen camera icon (see the next screenshot) and it will instantly reveal what’s stored in that QR Code. Also, if you scroll the results page, you’ll find Google search results for the text that was decoded from the QR Code.
I have tried this on a Nexus phone running Android 4.2.2 (JellyBean). Google Goggles is also integrated with the Google App for iOS devices.