An electricity meter is generally taken to be a device which measures the amount of electrical energy supplied to a customer of an electricity company. The most common type is more properly known as a (kilo)watt-hour meter or a joule meter.

Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter.

Newer electronic meters can be read automatically. One common means of semi-automated meter reading has a serial port on the meter that communicates by infrared LED through the faceplate of the meter. In some apartment buildings, a similar protocol is used, but in a wired bus using EIA-485 to connect all the meters to a single plug. The plug is often near the mailboxes. In the European Union, the most common infrared protocol is "FLAG", a simplified subset of mode C of IEC 1107. In the U.S. and Canada, the favoured infrared protocol is ANSI C12.18.

Remote meter reading is an application of telemetry. One protocol proposed for this purpose is DLM/COSEM which can operate over any medium. The data can be transmitted by Zigbee, WiFi, telephone lines or over the power lines themselves. Some meters can be read over the internet.