W3C provides a mobileOK checker to perform various tests on a Web Page to determine its level of mobile-friendliness. The tests are defined in the mobileOK Basic Tests 1.0 specification.
The checker is based on the open source mobileOK checker library developed by the Mobile Web Best Practices working group.
The mobileOK checker is part of the MobiWeb2.0 Project and of W3C Quality Assurance Tools.
mobileOK conformance can be claimed using POWDER.