°C or °F on the display (temperature unit)
The unit the reading is in: degrees Celsius or degrees Fahrenheit. A number that looks far too high or too low for a person is often just in the other unit.
Check your thermometer’s manual — makers differ.
What it is for
Check the unit before you read the number, and change it the way your own manual shows; each maker puts the setting somewhere different, and on some the change also affects the memory.
These pages report what each maker’s manual says and quote it wherever health is involved. They do not diagnose anything, they are not medical advice, and they do not tell you whether a temperature is a fever or what to do about it; only your own thermometer’s manual and your doctor or nurse can do that for the person you are looking after.
- What it looks like
- A small °C or °F next to the number, steady once a reading is shown.
- Names makers use
- °C / °F (every maker read); Temperature mode (°F) and Temperature mode (°C) (Omron ET720); Temperature measurement unit (Beurer)
Where makes differ
Omron sets the ET720 to °F by default; you switch it by holding START and then ON/MEM while the room temperature is showing, and Omron warns that switching deletes all the readings stored in memory. Braun ships the ThermoScan in °C; with it switched off, you hold the power button for about 3 seconds until °C, SET, °F, SET cycle on the screen. Braun’s No touch BNT 400 has a slide switch inside the battery compartment instead. Microlife’s IR 310 switches when you hold the M-button for 5 seconds with the thermometer off. Beurer’s FT 90 and FT 95 set the unit in the settings opened with the LIGHT/SET button, and the Withings Thermo sets it in the Withings Thermo app, which Withings says must communicate with the thermometer once before the display changes.
What it does not mean
Switching the unit does not change the measurement, only how it is shown. It is not a sign of a fault; but on the Omron ET720 it does clear the memory, so note any readings you need first.
Other symbols with the same shapes
Sources
No published standard we could check defines the symbols on a digital thermometer’s display, so this meaning is taken from 5 makers’ own manuals and support pages, each fetched and read on the date shown:
- Omron: Omron No-Touch Forehead Thermometer ET720 (MC-720-Z) — instruction manual (US, 5681249-5D, PDF) — Switching between °F and °C: “This unit is set to °F as default”; hold [START], then [ON/MEM] until °C appears; “When the unit is switched between °F and °C, all the readings stored in the memory are deleted.” Checked 2026-09-29.
- Braun: Braun ThermoScan 7 (IRT 6520) and ThermoScan 3 (IRT 6030) infrared ear thermometers — instruction manual (Asia-Pacific, PDF) — Changing the temperature scale: shipped with Celsius activated; with the thermometer off, hold the Power button, after about 3 seconds the display shows “° C / SET / ° F / SET”. Checked 2026-09-29.
- Braun: Braun No touch + forehead thermometer BNT 400 — instruction manual (Asia-Pacific, PDF) — Changing the temperature scale: the °C / °F switch is in the battery compartment; slide it to °C or °F. Checked 2026-09-29.
- Microlife: Microlife Ear Thermometer IR 310 — instruction manual (IB IR 310 N-V10, revision 2024-09-13, PDF) — Changing between Celsius and Fahrenheit: with the device off, press and hold the M-button for 5 seconds, then press the M-button to change between °C and °F. Checked 2026-09-29.
- Beurer: Beurer FT 95 non-contact thermometer — instructions for use (2021-06-22, PDF) — Setting the basic functions: the temperature measurement unit flashes; select °C or °F with MODE/MEM and confirm with LIGHT/SET. Checked 2026-09-29.
- Withings: Withings Thermo — user guide (v2.0, April 2018, PDF) — Changing the units: in the Withings Thermo app, Settings; the thermometer and the app “have to communicate once before the temperature unit change is reflected on the display”. Checked 2026-09-29.
Written in our own words; quotations are the makers’ wording.