Table of ContentsView AllTable of ContentsWhich Type to UseRemote InfraredOralArmpitRectalIn-EarForeheadMercuryTemperature RangesWhen to Call the DoctorFAQ
Table of ContentsView All
View All
Table of Contents
Which Type to Use
Remote Infrared
Oral
Armpit
Rectal
In-Ear
Forehead
Mercury
Temperature Ranges
When to Call the Doctor
FAQ
To ensure you get an accurate temperature reading, it is important to know whichthermometerto use and how to use it correctly.
Verywell / Kelly Miller
Types of Thermometers
Body temperature can be measured in a few different ways. Standard digital thermometers and manual (mercury) thermometers can be used to take a temperature in three ways:
Three other types of digital-only thermometers are available:
Remote infrared thermometers and digital thermometers are generally recommended for children and adults because they’re fast and accurate.For children, the American Academy of Pediatrics (AAP) recommends different types of digital thermometers based on age.
*Discard old rectal thermometer and buy a new one for oral use.
How to Clean a Thermometer
How to Use a Non-Contact Thermometer
Non-contact thermometers use infrared technology to measure skin temperature. They are held an inch or two away from the skin and can take a temperature from the forehead, temple, or wrist.
Also known as remote infrared or contactless thermometers, non-contact thermometers can be safely used on people of any age, including newborns.
Each device works slightly differently, so be sure to read the package instructions. In general, to take a temperature using a remote infrared thermometer:
While non-contact thermometers can be safely used on newborns, the AAP recommends rectal temperature over remote temperatures for children under 3 months of age due to accuracy.
Are Wrist Temperatures Accurate?
Wrist temperatures taken with non-contact remote infrared thermometers are fairly accurate. Research shows in some circumstances, remote wrist temperatures are more accurate than those taken in the center of the forehead but less accurate than those taken at the temples.
How to Take an Oral Temperature
Oral thermometers are commonly recommended for adults. However, they are not the best option for younger children.
To get an accurate oral temperature reading, a person needs to keep their mouth closed long enough to get a good reading. Children are usually able to do this around age 4.
To use an oral thermometer:
How to Take an Armpit Temperature
Armpit—or axillary—temperature is typically measured with a multiuse digital thermometer.
Despite being the least accurate method, schools and daycares often prefer taking axillary temperatures to avoid spreading germs.
To use an axillary thermometer:
What Armpit Temperature Is a Fever?An axillary temperature of 99 degrees F or higher is considered a fever—and a reason to keep your child home from school or daycare.The average normal body temperature taken via the armpit is 97.6 degrees F.
What Armpit Temperature Is a Fever?
An axillary temperature of 99 degrees F or higher is considered a fever—and a reason to keep your child home from school or daycare.The average normal body temperature taken via the armpit is 97.6 degrees F.
How to Take a Rectal Temperature
Rectal temperaturesare considered the most accurate method for checking a newborn’s temperature. The AAP recommends taking rectal temperature for all children under 3 months old and for children up to 4 years old.
Rectal temperatures are taken with a digital multiuse thermometer or manual mercury thermometer. (Be sure to clearly label it for rectal use only.)
To take a rectal temperature:
How to Use an In-Ear Thermometer
However, tympanic thermometers can be difficult to use on babies and may not be accurate because their ear canals are so small.
To use a tympanic thermometer:
Make sure excess earwax isn’t built up before using this method, as it can cause less accurate results.
How to Use a Forehead Thermometer
Forehead (temporal) thermometers read heat coming from the temporal artery, which is right under the skin of your forehead. These thermometers are fast and easy to use but may read too low at times.
Different varieties of temporal thermometers are available. In its earliest form, forehead thermometers measured temperature through skin contact.
Each model has different instructions for use. Be sure to consult the package instructions. In general, to use a temporal contact thermometer:
Mercury Thermometers
Mercury thermometers are no longer sold in the United States. They pose a danger if they break and release mercury, which is toxic.
If you have an old mercury thermometer, here is how to use it:
Interestingly, what’s average appears to have dropped over time. A 2017 study found that the average body temperature is closer to 97.88 degrees F than the often-cited 98.6 degrees F.
Not allfeversneed treatment. If a fever is making you uncomfortable, you can take over-the-counterfever reducerssuch as aspirin (adults only), Motrin or Advil (ibuprofen), or Aleve (naproxen).
Certain temperatures or symptoms do warrant medical attention, though.
When it comes to your child, you should call the doctor when:
For an adult, you should call the doctor if you have a fever:
When Is a Fever an Emergency?
A fever of 107.6 F can cause brain damage and is a life-threatening emergency. Seek emergency medical care for a fever of 105 F that does not quickly respond to treatment.
Summary
Knowing how to use a thermometer correctly can help ensure accurate temperature readings. The right thermometer to use depends on age.
Most people can get a fairly accurate reading using a quality non-contact infrared thermometer. However, the American Academy of Pediatrics still recommends using a multi-use digital thermometer to take a rectal temperature in children under 3 months old. Contactless thermometers can read temperatures at the temple, forehead, or wrist.
Body temperature can also be measured using a multiuse thermometer under the tongue or armpit, an in-ear thermometer, or a contact forehead thermometer. If you are unsure if the reading is accurate, try a different thermometer.
Frequently Asked Questions
Yes. However, the reading is 0.5 to 1 degree F lower than an oral reading, so an average body temperature with a forehead thermometer might read 97.6 to 98.1 instead of the normal 98.6.Learn MoreUnderstanding Normal Body Temperature
Yes. However, the reading is 0.5 to 1 degree F lower than an oral reading, so an average body temperature with a forehead thermometer might read 97.6 to 98.1 instead of the normal 98.6.
Learn MoreUnderstanding Normal Body Temperature
Contactless forehead thermometers are a good choice for screening for COVID. Anything over 100.5 F could be a sign of an infection, which could be COVID or another illness.Keep in mind: Using a forehead thermometer in direct sunlight and testing a child who has been running around or is overheated could give you an inaccurately high temperature.Learn MoreCOVID-19: Research and News
Contactless forehead thermometers are a good choice for screening for COVID. Anything over 100.5 F could be a sign of an infection, which could be COVID or another illness.Keep in mind: Using a forehead thermometer in direct sunlight and testing a child who has been running around or is overheated could give you an inaccurately high temperature.
Learn MoreCOVID-19: Research and News
Learn MoreSymptoms of a Fever
21 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. National Library of Medicine: MedlinePlus.Temperature measurement.American Academy of Pediatrics.Thermometers 101: how to check temperature during COVID-19 pandemic.Sulaski Wyckoff A.Thermometer use 101.AAP News.2009;30(11);29. doi:10.1542/aapnews.20093011-29aIcahn School of Medicine at Mount Sinai.Temperature measurement.Auf der Strasse W, Campos DP, Mendonça CJA, Soni JF, Mendes J, Nohama P.Forehead, temple and wrist temperature assessment of ethnic groups using infrared technology.Med Eng Phys. 2022;102:103777. doi:10.1016/j.medengphy.2022.103777Sollai S, Dani C, Berti E, Fancelli C, Galli L, de Martino M, Chiappini E.Performance of a non-contact infrared thermometer in healthy newborns.BMJ Open. 2016;6(3):e008695. doi:10.1136/bmjopen-2015-008695Centers for Disease Control and Prevention.General instructions for how to use an infrared thermometer.Chen G, Xie J, Dai G, et al.Validity of the use of wrist and forehead temperatures in screening the general population for COVID-19: a prospective real-world study.Iran J Public Health. 2020;49(Suppl 1):57-66. doi:10.18502/ijph.v49iS1.3670Uchida Y, Izumizaki M.The use of wearable devices for predicting biphasic basal body temperature to estimate the date of ovulation in women.J Therm Biol. 2022;108:103290. doi:10.1016/j.jtherbio.2022.103290American Academy of Pediatrics: HealthyChildren.org.How to take your child’s temperature.Penn Medicine.Fever.Zhu T, Sun X, Zhu D, et al.Role of daily anal stimulation for intractable functional constipation in infants.World J Pediatr Surg. 2020;3(2):e000135. doi:10.1136/wjps-2020-000135Mah AJ, Ghazi Zadeh L, Khoshnam Tehrani M, Askari S, Gandjbakhche AH, Shadgan B.Studying the accuracy and function of different thermometry techniques for measuring body temperature.Biology(Basel). 2021;10(12):1327. doi:10.3390/biology10121327El-Radhi AS.Determining fever in children: the search for an ideal thermometer.Br J Nurs.2014;23(2):91-94. doi:10.12968/bjon.2014.23.2.91Geijer H, Udumyan R, Lohse G, Nilsagård Y.Temperature measurements with a temporal scanner: systematic review and meta-analysis.BMJ Open. 2016;6(3):e009509. doi:10.1136/bmjopen-2015-009509U.S. Environmental Protection Agency.Mercury thermometers.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468U.S. National Library of Medicine: MedlinePlus.Fever.American College of Emergency Physicians.Fever.Mott Children’s Hospital.Fever Temperatures: Accuracy and Comparison.Teng CL, Ng CJ, Nik-Sherina H, Zailinawati AH, Tong SF.The accuracy of mother’s touch to detect fever in children: a systematic review. Journal of Tropical Pediatrics. 2007;54(1):70-73. doi:10.1093/tropej/fmm077Additional ReadingAmerican Academy of Pediatrics: healthychildren.org.How to take a child’s temperature.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468
21 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. National Library of Medicine: MedlinePlus.Temperature measurement.American Academy of Pediatrics.Thermometers 101: how to check temperature during COVID-19 pandemic.Sulaski Wyckoff A.Thermometer use 101.AAP News.2009;30(11);29. doi:10.1542/aapnews.20093011-29aIcahn School of Medicine at Mount Sinai.Temperature measurement.Auf der Strasse W, Campos DP, Mendonça CJA, Soni JF, Mendes J, Nohama P.Forehead, temple and wrist temperature assessment of ethnic groups using infrared technology.Med Eng Phys. 2022;102:103777. doi:10.1016/j.medengphy.2022.103777Sollai S, Dani C, Berti E, Fancelli C, Galli L, de Martino M, Chiappini E.Performance of a non-contact infrared thermometer in healthy newborns.BMJ Open. 2016;6(3):e008695. doi:10.1136/bmjopen-2015-008695Centers for Disease Control and Prevention.General instructions for how to use an infrared thermometer.Chen G, Xie J, Dai G, et al.Validity of the use of wrist and forehead temperatures in screening the general population for COVID-19: a prospective real-world study.Iran J Public Health. 2020;49(Suppl 1):57-66. doi:10.18502/ijph.v49iS1.3670Uchida Y, Izumizaki M.The use of wearable devices for predicting biphasic basal body temperature to estimate the date of ovulation in women.J Therm Biol. 2022;108:103290. doi:10.1016/j.jtherbio.2022.103290American Academy of Pediatrics: HealthyChildren.org.How to take your child’s temperature.Penn Medicine.Fever.Zhu T, Sun X, Zhu D, et al.Role of daily anal stimulation for intractable functional constipation in infants.World J Pediatr Surg. 2020;3(2):e000135. doi:10.1136/wjps-2020-000135Mah AJ, Ghazi Zadeh L, Khoshnam Tehrani M, Askari S, Gandjbakhche AH, Shadgan B.Studying the accuracy and function of different thermometry techniques for measuring body temperature.Biology(Basel). 2021;10(12):1327. doi:10.3390/biology10121327El-Radhi AS.Determining fever in children: the search for an ideal thermometer.Br J Nurs.2014;23(2):91-94. doi:10.12968/bjon.2014.23.2.91Geijer H, Udumyan R, Lohse G, Nilsagård Y.Temperature measurements with a temporal scanner: systematic review and meta-analysis.BMJ Open. 2016;6(3):e009509. doi:10.1136/bmjopen-2015-009509U.S. Environmental Protection Agency.Mercury thermometers.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468U.S. National Library of Medicine: MedlinePlus.Fever.American College of Emergency Physicians.Fever.Mott Children’s Hospital.Fever Temperatures: Accuracy and Comparison.Teng CL, Ng CJ, Nik-Sherina H, Zailinawati AH, Tong SF.The accuracy of mother’s touch to detect fever in children: a systematic review. Journal of Tropical Pediatrics. 2007;54(1):70-73. doi:10.1093/tropej/fmm077Additional ReadingAmerican Academy of Pediatrics: healthychildren.org.How to take a child’s temperature.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
U.S. National Library of Medicine: MedlinePlus.Temperature measurement.American Academy of Pediatrics.Thermometers 101: how to check temperature during COVID-19 pandemic.Sulaski Wyckoff A.Thermometer use 101.AAP News.2009;30(11);29. doi:10.1542/aapnews.20093011-29aIcahn School of Medicine at Mount Sinai.Temperature measurement.Auf der Strasse W, Campos DP, Mendonça CJA, Soni JF, Mendes J, Nohama P.Forehead, temple and wrist temperature assessment of ethnic groups using infrared technology.Med Eng Phys. 2022;102:103777. doi:10.1016/j.medengphy.2022.103777Sollai S, Dani C, Berti E, Fancelli C, Galli L, de Martino M, Chiappini E.Performance of a non-contact infrared thermometer in healthy newborns.BMJ Open. 2016;6(3):e008695. doi:10.1136/bmjopen-2015-008695Centers for Disease Control and Prevention.General instructions for how to use an infrared thermometer.Chen G, Xie J, Dai G, et al.Validity of the use of wrist and forehead temperatures in screening the general population for COVID-19: a prospective real-world study.Iran J Public Health. 2020;49(Suppl 1):57-66. doi:10.18502/ijph.v49iS1.3670Uchida Y, Izumizaki M.The use of wearable devices for predicting biphasic basal body temperature to estimate the date of ovulation in women.J Therm Biol. 2022;108:103290. doi:10.1016/j.jtherbio.2022.103290American Academy of Pediatrics: HealthyChildren.org.How to take your child’s temperature.Penn Medicine.Fever.Zhu T, Sun X, Zhu D, et al.Role of daily anal stimulation for intractable functional constipation in infants.World J Pediatr Surg. 2020;3(2):e000135. doi:10.1136/wjps-2020-000135Mah AJ, Ghazi Zadeh L, Khoshnam Tehrani M, Askari S, Gandjbakhche AH, Shadgan B.Studying the accuracy and function of different thermometry techniques for measuring body temperature.Biology(Basel). 2021;10(12):1327. doi:10.3390/biology10121327El-Radhi AS.Determining fever in children: the search for an ideal thermometer.Br J Nurs.2014;23(2):91-94. doi:10.12968/bjon.2014.23.2.91Geijer H, Udumyan R, Lohse G, Nilsagård Y.Temperature measurements with a temporal scanner: systematic review and meta-analysis.BMJ Open. 2016;6(3):e009509. doi:10.1136/bmjopen-2015-009509U.S. Environmental Protection Agency.Mercury thermometers.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468U.S. National Library of Medicine: MedlinePlus.Fever.American College of Emergency Physicians.Fever.Mott Children’s Hospital.Fever Temperatures: Accuracy and Comparison.Teng CL, Ng CJ, Nik-Sherina H, Zailinawati AH, Tong SF.The accuracy of mother’s touch to detect fever in children: a systematic review. Journal of Tropical Pediatrics. 2007;54(1):70-73. doi:10.1093/tropej/fmm077
U.S. National Library of Medicine: MedlinePlus.Temperature measurement.
American Academy of Pediatrics.Thermometers 101: how to check temperature during COVID-19 pandemic.
Sulaski Wyckoff A.Thermometer use 101.AAP News.2009;30(11);29. doi:10.1542/aapnews.20093011-29a
Icahn School of Medicine at Mount Sinai.Temperature measurement.
Auf der Strasse W, Campos DP, Mendonça CJA, Soni JF, Mendes J, Nohama P.Forehead, temple and wrist temperature assessment of ethnic groups using infrared technology.Med Eng Phys. 2022;102:103777. doi:10.1016/j.medengphy.2022.103777
Sollai S, Dani C, Berti E, Fancelli C, Galli L, de Martino M, Chiappini E.Performance of a non-contact infrared thermometer in healthy newborns.BMJ Open. 2016;6(3):e008695. doi:10.1136/bmjopen-2015-008695
Centers for Disease Control and Prevention.General instructions for how to use an infrared thermometer.
Chen G, Xie J, Dai G, et al.Validity of the use of wrist and forehead temperatures in screening the general population for COVID-19: a prospective real-world study.Iran J Public Health. 2020;49(Suppl 1):57-66. doi:10.18502/ijph.v49iS1.3670
Uchida Y, Izumizaki M.The use of wearable devices for predicting biphasic basal body temperature to estimate the date of ovulation in women.J Therm Biol. 2022;108:103290. doi:10.1016/j.jtherbio.2022.103290
American Academy of Pediatrics: HealthyChildren.org.How to take your child’s temperature.
Penn Medicine.Fever.
Zhu T, Sun X, Zhu D, et al.Role of daily anal stimulation for intractable functional constipation in infants.World J Pediatr Surg. 2020;3(2):e000135. doi:10.1136/wjps-2020-000135
Mah AJ, Ghazi Zadeh L, Khoshnam Tehrani M, Askari S, Gandjbakhche AH, Shadgan B.Studying the accuracy and function of different thermometry techniques for measuring body temperature.Biology(Basel). 2021;10(12):1327. doi:10.3390/biology10121327
El-Radhi AS.Determining fever in children: the search for an ideal thermometer.Br J Nurs.2014;23(2):91-94. doi:10.12968/bjon.2014.23.2.91
Geijer H, Udumyan R, Lohse G, Nilsagård Y.Temperature measurements with a temporal scanner: systematic review and meta-analysis.BMJ Open. 2016;6(3):e009509. doi:10.1136/bmjopen-2015-009509
U.S. Environmental Protection Agency.Mercury thermometers.
Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468
U.S. National Library of Medicine: MedlinePlus.Fever.
American College of Emergency Physicians.Fever.
Mott Children’s Hospital.Fever Temperatures: Accuracy and Comparison.
Teng CL, Ng CJ, Nik-Sherina H, Zailinawati AH, Tong SF.The accuracy of mother’s touch to detect fever in children: a systematic review. Journal of Tropical Pediatrics. 2007;54(1):70-73. doi:10.1093/tropej/fmm077
American Academy of Pediatrics: healthychildren.org.How to take a child’s temperature.Obermeyer Z, Samra JK, Mullainathan S.Individual differences in normal body temperature: longitudinal big data analysis of patient records.BMJ. 2017;359:j5468. doi:10.1136/bmj.j5468
American Academy of Pediatrics: healthychildren.org.How to take a child’s temperature.
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