List of computer size categories

Supercomputers

• Minisupercomputer

Mainframe computers

Minicomputers

• Superminicomputer
• Minicluster (SFF / ITX)^[1]
• Server
• Workstation

Microcomputers

• Tower PC
• Mid-Tower PC
• Mini-Tower PC
• Server
• Workstation
• Personal computer (PC)
  • Desktop computer
  • Home computer
  • Microsoft Surface

Mobile computers

• Desktop replacement computer or desknote
• Laptop computer
  • Notebook computer
    • Subnotebook computer, also known as a Kneetop computer; clamshell varieties may also be known as minilaptop or ultraportable laptop computers
  • Tablet personal computer
  • "slabtop" computers including "word-processing keyboards" and the TRS-80 Model 100
  • Handheld computers, which include the classes:
    • Ultra-Mobile personal computer, or UMPC
    • Personal digital assistant or enterprise digital assistant, which include:
      • HandheldPC or Palmtop computer
      • Pocket personal computer
    • Electronic organizer
    • Pocket computer
    • Calculator, which includes the class:
      • Graphing calculator
      • Scientific calculator
      • Programmable calculator
      • Accounting / Financial Calculator
    • Handheld game console
    • Portable media player
    • Portable data terminal
    • Information appliance
      • Q Smartphone,(QWERTY Smartphone) a class of mobile phone
      • Smartphone, a class of mobile phone
  • Wearable computer
• Single board computer
• Wireless sensor network components
• Plug computer
• Microcontroller
• Smartdust
• Nanocomputer

Others

• Deskside computer - often strd. rack width but less than half of the typical rack height, esp. for mid-range servers (e.g. RS/6000 7025-F80), visualisation (e.g. Onyx Deskside) or vector processing (e.g. SX-6i).
• Cart computer
• Microsoft Sphere
• Rackmount/Framemount computer
  • Multimedia server
  • Blade server
  • Blade PC

• Small form factor personal computer (SFF, ITX, DTX...etc.)

Source: Wikipedia.com