A laptop computer or simply laptop (also notebook computer or notebook) is a small mobile personal computer, which usually weighs 2.2-12 pounds (1-6 kilograms), depending on size, materials and other factors.

Terms sometimes used for subtypes of laptop computers include:

Ultraportables

Laptops with screens typically less than 12 inches diagonally and a weight of less than 1.7kg. Their keyboards are usually not full-size. Their primary audience is usually business travelers, who need small, light laptops. Ultraportables are often very expensive, have extended battery and/or battery life, house power-saving CPUs and almost always have integrated graphics.

Thin-and-lights

Laptops usually weighing in between 1.8kg and 2.8kg with a screen size of between 12 and 14 inches diagonally.

Medium-sized laptops

These usually have screens of 15 - 15.4 inches diagonally and a weight of around 3-3.5kg. They usually sacrifice a little computing power for smaller dimensions and longer battery life, although the length and width are usually determined by the screen size.

Desktop replacement computers

Powerful laptops meant to be mainly used in a fixed location and infrequently carried out due to their weight and size; the latter provides more space for powerful components and a big screen, usually measuring 15 inches or more. Desktop replacements tend to have limited battery life, rarely exceeding three hours, because the hardware is not optimized for efficient power usage.

School Programs

Many schools have taken in laptop based programs in which every student receives a laptop for school use only. An operating system or other program is installed to limit the student's access to perform administrative tasks such as hardware or software installation, or operating system modifications. Students are generally permitted to use these systems to take notes, write papers, and perform other school-related activities.