Updated: 11/12/2023 by Computer Hope

A button may refer to any of the following:

Computer power button

1. With hardware, a button is a physical switch that controls a device's function. The picture shows the power button found on the front of a computer.

What does the power button do?

  • If the computer is off and the power button is pressed, the computer turns on.
  • Many computers have a button with an LED (light-emitting diode) to also indicate if the computer is on or off.
  • If the computer is sleeping and the light is flashing, the power button will wake up the computer.
  • More modern computers pressing and letting go of the power button puts the computer into sleep mode or turns off the computer with a proper shutdown process.
  • With newer computers, if the computer is on, pressing and holding the power button for three to five seconds turns the computer off. Realize this should only be done when the computer cannot turn off by itself.

For information about how computers work, see: How does a computer work?

What is the power button symbol?

Standby symbol IEC 60417

The standard symbol for the power button is the "standby symbol," as defined by the IEC (International Electrotechnical Commission). The symbol combines a vertical line and a circle, representing "on" and "off," respectively. It's defined in IEC 60417, Graphical Symbols for Use on Equipment. The symbol also resembles a "1" and "0," the binary numbers representing "on" and "off."

What is the power button key?

Desktop and laptop computer keyboards have no key that's used to turn on the computer. Instead, use the power button (mentioned below) on the computer case to turn on the computer.

Where is the power button located?

Desktop computer

On a desktop computer, the power button is often on the front or top of the case. In most cases, there is a power button symbol on or next to the power button, which helps identify it.

Power button on a desktop computer

Laptop computer

On a laptop, the power button is often found above the keyboard, on the left or right side. It may also be on the far-left or far-right on the top row of keys on the keyboard. If you cannot find the power button, check the left or right edge of the laptop instead.

Power button on a laptop computer

Mobile device

On mobile computing devices, like a tablet or smartphone, the power button is often on the top or right edge. However, some brands may place the power button on the left or bottom edge instead. To locate the power button, look for a single button set apart from others, as shown below.

Power button on a smartphone


On a printer, the power button is often on the top or front panel, and may have the power button symbol. If the printer has a printer screen, the power button is often next to that. Some older printers have a power switch on the back corner of the printer.

Power button on a printer

Are computer keyboard keys buttons?

The "buttons" on a keyboard are called keys, not buttons. For example, Ctrl is called the "Ctrl key" and not the "Ctrl button."

What are the mouse buttons?

Today, all computer mice have multiple, clickable buttons to perform certain actions. See our mouse button page for further information about these buttons.

What are printer buttons?

Printer buttons are buttons found on the front of a computer printer. These buttons may include a power button, settings button, go and stop button, and a Wi-Fi button.


If your printer has a printer screen, most of the buttons that accessed printer functions are now controlled through the printer screen.

How many buttons does a computer have?

Today, most computers only have one or two buttons: the power button and sometimes a reboot button. Some other buttons found on earlier and specialty computers can be any or all of the following.


We're only including the buttons found on a computer case and not keyboard keys, mouse buttons, monitor buttons, or other buttons found on other peripherals.

2. With software, a button is a graphic icon that may have text that performs a software function. For example, the Windows Start button opens the Start menu. See the push-button dictionary definition for further information and an example.

3. When writing in HTML (hypertext markup language), the <button> tag creates a clickable button.

Default button, Depress, Mouse button, Office button, Power terms, Push-button, PWRSW, Reset button, Start button, Turbo button