How to Change Any Digital or Infrared Thermometer from °C to °F

Download Article

Learn how to switch the temperature settings on your thermometer

Co-authored by Hannah Dillon Reviewed by Luigi Oppido

Last Updated: October 1, 2025 Fact Checked

Download Article

One-Button Digital Thermometers

|

Forehead Thermometers

|

Infrared Thermometers

|

Video

|

Tips

If you've ever turned on your thermometer and noticed the display is in Celsius instead of Fahrenheit (or vice versa), don't worry: Swapping to your preferred setting is very simple. Whether yours is under-the-tongue, forehead, or infrared, keep reading to learn how to switch the temperature mode on various digital thermometers.

Changing a Thermometer from °C to °F

Press and hold the power button to swap modes on one-button thermometers, or on some in-ear thermometers.
Push the °C/°F or settings button on forehead thermometers. You may need to use the arrow buttons or the +/- buttons to switch settings.
Flick the switch in the battery compartment of infrared thermometers.

Method 1

Method 1 of 3:

One-Button Digital Thermometers

Download Article

1
Turn the thermometer off. For digital thermometers with one button, the power button often doubles as the control for changing from °C to °F. To start, make sure the thermometer is off.^{[1]
X
Research source}
- Thermometers like this include the basic under-the-tongue digital thermometers by Vicks, Walgreens, Omron, and more.
- These steps will also work for the Braun ThermoScan ear thermometer.^{[2]
  X
  Research source}
As you turn the thermometer back on, don't lift your finger off the button. This will let the thermometer know you are trying to change modes and not just turn it on.^{[3]
X
Research source}

Advertisement
3
Release the button after you see the temperature mode change. Check for °F in the corner of the screen. Your thermometer may also beep after you've changed modes.^{[4]
X
Research source}
- Rather than a blinking °F, your thermometer may display the phrase "F-SET" to show you've changed modes.
- If your thermometer flashes a °C or reads out "C-SET," you've switched into Celsius. Repeat the process, and it will switch back.

Method 2

Method 2 of 3:

Forehead Thermometers

Download Article

1
Find the settings button. This button may be labeled with MODE, SET, MEM, or START. It may also be marked by a symbol, like a person or a speaker. Press and hold to change from °C to °F.^{[5]
X
Research source}
- HoMedics, Equate, and other electronic thermometer manufacturers include labeled settings buttons on their products.
2
Press the ON button. Some thermometers require you to press the ON button while holding down the settings button to switch from °C to °F.
- Some Omron forehead thermometers have an ON/MEM button that you must press while holding down START to switch their temperature settings.^{[6]
  X
  Research source}
3
Press the arrow or +/- buttons to switch to °F. On some thermometers, pushing the settings button lets the user change multiple settings, not just °C and °F. In this case, press the button several times to open the temperature settings, then use the arrows or the +/- buttons to switch to °F.^{[7]
X
Research source}
- You'll know you're in the temperature settings when the °C on the screen begins to flash or changes to °F.
Frontal scanning thermometers sometimes have a button specifically labeled °C/°F. Look on the front or the side of your thermometer to see if you have one. If so, use this button to freely change between Celsius and Fahrenheit.^{[8]
X
Research source}

Method 3

Method 3 of 3:

Infrared Thermometers

Download Article

1
Press the settings button. Most of the time, this button will be labeled MODE or SET. Push it to change the temperature settings. Pushing the button once may be enough to change from °C to °F. However, you may need to press several times to open the temperature settings and change from there.^{[9]
X
Research source}
- To know whether you're in the temperature unit settings, check the screen. The current unit will be flashing. Change it by pushing the arrow keys.
- For some infrared thermometers produced by Klein Tools, Beurer, and other manufacturers, the settings button won't change the temperature unit. Instead, that button is used to set warning alarms, degree variation, and other modes. The temperature unit controls are in the battery compartment.
2
If the setting button doesn't work, open the battery compartment. Look for the groove on the side of the thermometer handle. Slide your thumb into the groove and push forward to pop open the compartment. Infrared thermometers often have their temperature unit controls here.^{[10]
X
Research source}
- If the battery compartment cover is too tight, slide the tip of a flathead screwdriver in the space between the cover and the handle. Then, wiggle the screwdriver enough to pop the compartment open. Don't push too hard; otherwise, the screwdriver could break the plastic or come in contact with the batteries.
Toggle it towards the "°F" position to display the temperature in Fahrenheit. Flip it back to return it to Celsius.^{[11]
X
Research source}