How to Change One-Button, Frontal, and Infrared Thermometers from °C to °F

Co-authored by Krysten Jackson Reviewed by Luigi Oppido

Last Updated: September 14, 2024 Fact Checked

Your new digital thermometer can help you quickly and accurately take temperatures, sometimes without even making contact. If you’ve turned on your thermometer and noticed the display is in Celsius instead of Fahrenheit, rest assured that swapping to your preferred setting is very simple. Whether yours is under-the-tongue or infrared, keep reading to know how to switch the temperature mode on all sorts of digital thermometers.

Things You Should Know

Press and hold the power button to swap modes on one-button thermometers.
Push the “°C/°F” or settings buttons on frontal thermometers. You may need to use the arrow buttons or the ‘+’ and ‘-’ buttons to switch settings.
Flick the switch in the battery compartment of infrared thermometers.

Method 1

Method 1 of 3:

One Button Digital Thermometers

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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]
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- Thermometers like this include the basic digital thermometers by Vicks, Walgreens, Omron, and more.
As you turn the thermometer back on, don’t lift your finger off of the button. This will let the thermometer know you are trying to change modes and not just turn it on.^{[2]
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Release the button after you see the temperature mode change. Check for an °F in the corner of the screen. Your thermometer may also beep after you’ve changed modes.^{[3]
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- 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:

Electronic and Frontal Thermometers

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Find the settings button. This button may be labeled with, for example, “MODE,” “SET,” or “MEM.” It may also be marked by a symbol, like a person or a speaker. Press and hold to change from °C to °F.^{[4]
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- HoMedics, Equate, and other electronic thermometer manufacturers include labeled settings buttons on their products.
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Press the arrow or ‘+’ and ‘-’ 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 ‘+’ and ‘-’ buttons to switch to °F.^{[5]
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- You’ll know you’re in the temperature settings when the °C on the screen begins to flash or changes to an °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.^{[6]
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Method 3

Method 3 of 3:

Infrared Thermometers

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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.^{[7]
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- 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.
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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.^{[8]
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- If the battery compartment cover is too tight, slide the tip of a flathead screwdriver in the space between the cover in the handle. Then, wiggle the screwdriver enough to pop the compartment open. Don’t push too hard so that that screwdriver doesn’t 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.^{[9]
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