A smartwatch is a portable wearable computer that resembles a wristwatch. Most modern smartwatches are operated via a touchscreen, and rely on mobile apps that run on a connected device (such as a smartphone) in order to provide core functions.

Early smartwatches were capable of performing basic functions like calculating, displaying digital time, translating text, and playing games. More recent models often offer features comparable to smartphones, including apps, a mobile operating system, Bluetooth and Wi-Fi connectivity, and the ability to function as portable media players or FM radios. Some high-end models have cellular capabilities, allowing users to make and receive phone calls.

While internal hardware varies, most smartwatches have a backlit LCD or OLED electronic visual display and are powered by a rechargeable lithium-ion battery. They may also incorporate GPS receivers, digital cameras, and microSD card readers, as well as various internal and environmental sensors such as thermometers, accelerometers, altimeters, barometers, gyroscopes, and ambient light sensors. Some smartwatches also function as activity trackers and include body sensors such as pedometers, heart rate monitors, galvanic skin response sensors, and ECG sensors. Software may include maps, health and exercise-related apps, calendars, and various watch faces.