A remarkable variety of mobile computing devices are available, ranging from advanced cell phones to small hand-help personal computers to tablet personal computers and lightweight laptops. Every month sees the release of a better, faster, or cheaper device.

Among the most widely used devices are advanced cell phones, combining the functions of a tablet computer and a cellular telephone. Advanced cell phones are designed for limited data input with thumb keyboards or on-screen virtual keyboards. Suitable activities on the limited screen size include reference applications designed for the form such as electronic pharmacopoeia, and applications for charge capture, limited note-taking, and e-mail. Lightweight forms of decision support, such as medical calculators, opiate dose-equivalent converters, and drug-drug interaction checkers are widely used. Large data entry tasks such as clinical documentation or full-scale order-writing is not realistic on these devices. Clinical information systems vendors are increasingly offering stripped-down user interfaces for small devices, and several bolt-on applications are available.