Computer hardware is a collective term used to describe any of the physical components of an analog or digital computer. The term hardware distinguishes the tangible aspects of a computing device from software, which consists of written instructions that tell physical components what to do.

Computer hardware can be categorized as having either internal or external components. Internal components include items such as the motherboard, central processing unit (CPU), random access memory (RAM), hard drive, optical drive, heat sink, power supply, transistors, chips, graphics processing unit (GPU), network interface card (NIC) and Universal Serial Bus (USB) ports. These components collectively process or store the instructions delivered by the program or operating system (OS).

External components, also called peripheral components, are those items that are often connected to the computer in order to control either its input or output. Common input components include a mouse, keyboard, microphone, camera, touchpad, stylus, joystick, scanner, USB flash drive or memory card. Monitors, printers, speakers, headphones and earphones/earbuds are all examples of output computer hardware components. All these hardware devices are designed to either provide instructions to the software or render results from its execution.