Forehead thermometer
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- Non-contact infrared forehead thermometer. Best for: Quick, no-touch checks for the whole family. See options on Amazon
- Frida 3-in-1 infrared thermometer. Best for: Families wanting ear and forehead modes in one. See options on Amazon
How forehead thermometers work
The FDA describes non-contact infrared thermometers (NCITs) as a way to measure a person's surface temperature. Benefits it lists include a non-contact approach that may reduce the risk of spreading disease, ease of use, easy cleaning and disinfecting, rapid readings, and the ability to retake a temperature quickly. Its limitation: how and where the thermometer is used, such as head covers, the environment and positioning on the forehead, may affect the measurement.
Some thermometers combine modes, such as ear and forehead readings in one device. Whatever type you buy, the FDA says to strictly follow the manufacturer's guidelines and instructions for that specific thermometer.
FDA steps for an accurate reading
| Step | What to do | Why |
|---|---|---|
| Room | Use in a draft-free space, out of direct sun and away from radiant heat | The environment affects performance |
| Conditions | Room between 60.8 and 104°F (16 to 40°C), humidity below 85% | Typical optimal range in instructions |
| Acclimate | Leave the thermometer in the room 10 to 30 minutes first | Lets it adjust to the environment |
| Forehead | Clean, dry and not blocked | The FDA lists this as preparation for the person |
| Position | Hold the sensor perpendicular to the forehead at the maker's distance | Angle and distance affect accuracy |
Steps are from the FDA's guidance on non-contact infrared thermometers, which says to strictly follow the instructions for your specific model.
Before you measure
The FDA says the person being checked should not have had their forehead temperature raised or lowered by heavy clothing or head covers such as headbands or bandanas, or by facial cleansing products such as cosmetic wipes. Have the person stay still during the measurement. Do not touch the sensing area, and keep the sensor clean and dry.
MedlinePlus adds general advice for any temperature: wait at least 1 hour after heavy exercise or a hot bath before measuring.
How accurate are forehead thermometers?
MedlinePlus says a forehead scanner reading is most often 0.5 to 1°F (0.3 to 0.6°C) lower than an oral temperature. It also says electronic forehead thermometers are more accurate than ear thermometers and similar in accuracy to probe thermometers, while plastic forehead strips are the least accurate and not recommended for general home use.
The FDA notes that normal body temperature can range from 97°F (36.1°C) to 99°F (37.2°C), and that improper use of these thermometers may lead to inaccurate readings. Tell your provider which type of thermometer you used. For a probe thermometer, see our digital thermometer guide.
For comparison, MedlinePlus gives these general guidelines against an average oral temperature of 98.6°F (37°C): rectal and ear readings are 0.5 to 1°F higher, and armpit and forehead readings 0.5 to 1°F lower. The exact relationship between methods is unclear, it says, so use the same method each time when tracking a fever.
Cleaning and care
- Follow the cleaning and disinfecting section of your thermometer's instructions between uses.
- The FDA says most non-contact thermometers should never be immersed in water or other liquids.
- Do not touch the sensing area, and keep the sensor clean and dry.
The FDA notes that non-contact thermometers may be used to reduce cross-contamination risk, but that the close distance needed to take a temperature still carries some risk of spreading disease between the two people. Wash your hands after checking someone who is sick. For cleaning wipes, see our antiseptic wipes guide, but check that your model's instructions allow them.
When to call a doctor
MedlinePlus says a temperature over 100.4°F (38°C) most often means a fever. For babies, especially those 3 months or younger, use the method your pediatrician recommends and call promptly with a fever; see the thresholds in our digital thermometer guide. For other home tools, see our pulse oximeter guide.
What to look for when you buy
Non-contact infrared forehead thermometer
Best for: Quick, no-touch checks for the whole family
The FDA lists fast readings, easy cleaning and a non-contact approach among the benefits.
Watch out: Use indoors, out of drafts and sun, at the maker's distance.
See options on AmazonFrida 3-in-1 infrared thermometer
Best for: Families wanting ear and forehead modes in one
It is sold for ear, forehead and touchless readings, and MedlinePlus rates forehead readings as similar in accuracy to probe thermometers.
Watch out: Use the same mode each time when tracking a fever.
See options on AmazonQuestions people ask
- Are forehead thermometers accurate?
- MedlinePlus says electronic forehead thermometers are similar in accuracy to probe thermometers, though readings are most often 0.5 to 1°F lower than oral.
- Why does my forehead thermometer give different readings?
- The FDA says the environment, head covers and positioning on the forehead can all affect the measurement.
- Can I use a forehead thermometer outside?
- The FDA says use it out of direct sun and drafts, within the room range in your instructions.
- How far from the forehead should I hold it?
- The distance is specific to each model; check the manufacturer's instructions.
- Do I need to let the thermometer warm up?
- The FDA says place it in the room 10 to 30 minutes before use to adjust.
Sources
- Non-contact Infrared Thermometers (fda.gov), U.S. Food and Drug Administration
- Temperature measurement (medlineplus.gov), MedlinePlus, U.S. National Library of Medicine
- Body temperature norms (medlineplus.gov), MedlinePlus, U.S. National Library of Medicine