Editor’s note: Originally published April 2021. Reviewed and updated November 2026.
Medical disclaimer: This article is general information, not medical advice. Ask a doctor or pharmacist about your situation.
Quick answer
- Wipe the thermometer with a cotton ball or swab soaked in rubbing alcohol (at least 60% alcohol), let it air dry, then store it.
- Rinse with cold water afterwards if you want to remove the alcohol smell.
- Soap and water works for glass and analog thermometers; on digital thermometers clean only the tip and keep water away from the electronics.
- For ear and infrared/forehead thermometers, gently clean the sensor or lens with an alcohol-soaked swab.
- Use separate thermometers for oral and rectal readings, and always follow the manufacturer’s cleaning instructions.
To clean a thermometer, wipe it thoroughly with rubbing alcohol on a cotton ball or swab, let it air dry, and store it only once it is completely dry. Digital thermometers need extra care: clean the tip and probe, but don’t soak the electronics. Because thermometers touch skin, mouths and other body sites, cleaning them before and after each use helps stop germs passing from person to person.
Before you start
- Check the manual. Manufacturer instructions take priority, especially for digital, ear and forehead models.
- Dedicate thermometers to one use. Digital thermometers can be used orally, under the arm or rectally, but don’t use the same thermometer in different locations. Label one for oral use and one for rectal use.
- Use enough alcohol. Rubbing alcohol with at least 60% alcohol is the basis of the methods below.
For guidance on getting an accurate reading at each body site, see how to take a temperature.
How to clean a thermometer step by step
This method works for both digital and traditional (analog) thermometers.
- Soak a cotton ball in rubbing alcohol.
- Wipe the whole thermometer, starting at the tip, without missing any corners, curves or ridges.
- Let the thermometer air dry.
- If you want to remove the alcohol smell, rinse the tip with cold water.
- Don’t store the thermometer until it is completely dry.
Alternative: soap and water
- Rinse the thermometer under the tap.
- Apply soap.
- Rinse again until all the soap is gone.
- Dry it thoroughly.
This works well on glass and analog thermometers. On a digital thermometer, water and soap can damage the electronics, so wash only the tip and avoid the display and battery compartment.
Cleaning infrared and forehead thermometers
Non-contact infrared thermometers don’t touch the skin, but they still benefit from regular cleaning, and models that touch the forehead should be cleaned after each use. Wipe the body and the sensor lens gently with a pre-soaked alcohol swab (at least 60% alcohol) and let it dry.
Cleaning ear thermometers
Ear thermometers have a small sensor at the tip. Clean it gently with a cotton swab dipped in rubbing alcohol (at least 60% alcohol) and let it dry before the next use.
Looking for a new thermometer? See our guides to clinical thermometers, medical infrared thermometers and the Braun ThermoScan 7 ear thermometer.
FAQ
How do you sanitize a thermometer against germs and viruses?
Clean first, then disinfect. Wash the part that touched the patient with soap and water (only the tip on a digital thermometer), then wipe the whole thermometer with a cotton swab soaked in at least 60% alcohol, covering every surface. Let it air dry.
Can you clean a thermometer with hand sanitizer?
Yes, an alcohol-based sanitizer can be used, but keep it away from the display, buttons and battery compartment of a digital thermometer, as liquid getting into the electronics can cause it to malfunction.
How do you clean a thermometer from bulb to stem?
Use the same method: wash with soap and clean water if appropriate, then wipe from the bulb up the stem with an alcohol-soaked cotton swab. Rinse with clean water if an alcohol smell remains.
Can I use thermometer cleaning wipes?
Yes. Pre-soaked alcohol wipes work, or you can make your own by soaking cotton in rubbing alcohol with at least 60% alcohol.
How do you clean a thermometer with hydrogen peroxide?
- Wash the thermometer with soap and water first. On a digital thermometer, clean only the tip.
- Fill a jar with enough hydrogen peroxide to cover the part you are cleaning (only the tip of a digital thermometer).
- Leave it to soak for at least 20 minutes.
- Lay the thermometer on a clean towel and let it dry completely.
- Store it in its case or a clean, dry place.
Can I clean a thermometer with Dettol?
It is better to avoid it. Antiseptic liquids like Dettol are made for other purposes; stick with rubbing alcohol or the cleaner your thermometer’s manufacturer recommends.
Final tip
Cleaning a thermometer only takes a minute, but the method matters. Use alcohol for disinfecting, keep liquid away from electronics, let it dry fully before storing, and follow the manufacturer’s instructions for your model.
