How to Take a Temperature

When it comes to taking someone's temperature, use the method that will give the most accurate reading. For babies and children under five years of age, taking a rectal temperature is most accurate. For older children and adults, taking an oral temperature is perfectly fine. As an alternative for people of any age, you may take an axillary (armpit) temperature, but this method is not as accurate as the others and should not be relied upon if you're worried the person has a fever.

Choose a Method

  1. Oral: For adults or older children. Infants cannot hold the thermometer in their mouth.
  2. Armpit: Too inaccurate for use on infants. Use for a quick check, then switch to another method if the result is above 99 °F (37 °C).
  3. Rectal: Recommended method for infants due to greater accuracy.
  4. Ear: Only use for adults and children older than 6 months. Works well for checking temperatures quickly without discomfort.
  5. Forehead: Works well for any age. Must use a digital thermometer if you want the most accuracy.
Method 1
Method 1 of 5:

Taking Oral Temperature

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    Use a multi-use or oral digital thermometer. Some digital thermometers are designed to be used either rectally, orally, or in the armpit, while others are designed to be used specifically in the mouth. Either type of thermometer will give an accurate reading. You can find digital thermometers in the drugstore.
    • If you have an old glass thermometer, it's best to stop using it. Glass thermometers are considered unsafe now because they contain mercury, which is poisonous to the touch. If the thermometer breaks, you will have a hazardous situation.
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    Wait 20–30 minutes after bathing or eating. A warm bath could affect the child's body temperature, so wait a good 20 minutes to make sure you get the most accurate possible reading.[1]
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    Prepare the tip of the thermometer. Clean it with rubbing alcohol soap and warm water, then rinse it with cool water and dry it thoroughly. [2]
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    Turn on the thermometer and insert it under the tongue. Make sure the tip is completely in the mouth and under the tongue, not up near the lips. The person's tongue should completely cover the tip of the thermometer.
    • If you're taking your child's temperature, either hold the thermometer in place or instruct your child to do so.
    • Try to move the thermometer as little as possible. If the person is upset, fidgeting, or vomiting, take their temperature under their arm instead.
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    Remove the thermometer when it beeps. Look at the digital display to determine whether the person has a fever. Any temperature above 100.4 °F (38.0 °C) is considered a fever. If a baby has even a slight fever, contact your doctor. However, children and adults don't need to go to the doctor unless their temperature is over 101 °F (38 °C).[3]
    • You may not need to go in for a doctor's visit, but it's best to get and follow your doctor's advice.
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    Wash the thermometer before putting it away. Use warm, soapy water and dry it thoroughly before putting it away for next time.
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Method 2
Method 2 of 5:

Taking Axillary (Armpit) Temperature

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    Use a multi-use digital thermometer. Look for a digital thermometer designed to be used either rectally, orally, or in the armpit. This way you can take the axillary temperature first, and if a high temperature is indicated, you can try a different method as well.
    • It's best to dispose of old glass thermometers, if you still have one. If they break, the mercury inside them is hazardous.
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    Turn on the thermometer and place it in the armpit. Lift the arm, insert the thermometer, then lower the arm so the tip of the thermometer is snug in the middle of the armpit. The entire tip should be covered.[4]
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    Remove the thermometer when it beeps. Look at the digital display to determine whether the person has a fever. Any temperature above 100.4 °F (38.0 °C) is considered a fever, but going to the doctor right away isn't necessary unless the fever is above a certain temperature:
    • If your baby has any signs of fever, call the doctor for any fever.
    • If the person with the fever is an older child or an adult, call the doctor if it's 101 °F (38 °C) or higher.
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    Wash the thermometer before putting it away. Use warm, soapy water and dry it thoroughly before putting it away for next time.
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Method 3
Method 3 of 5:

Taking Rectal Temperature

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    Use a multi-use or rectal digital thermometer. Some digital thermometers are designed to be used either rectally, orally, or in the armpit, while others are designed to be used specifically in the rectum. Either type of thermometer will give an accurate reading. You can find digital thermometers in the drugstore.
    • Look for a model that has a wide handle and a tip that can't be inserted too far into the rectum. This will make the process easier and help prevent you from inserting the thermometer too far.[5]
    • Avoid using old glass thermometers, which are now considered unsafe. If they break, the mercury inside them is hazardous.
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    Wait 20 minutes after bathing or swaddling. A warm bath or a snug swaddling session could affect the child's body temperature, so wait a good 20 minutes to make sure you get the most accurate possible reading.[6]
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    Prepare the tip of the thermometer. Clean it with rubbing alcohol soap and warm water, then rinse it with cool water and dry it thoroughly. Cover the tip with petroleum jelly to make it easier to insert.[7]
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    Position the child comfortably. Place the child either tummy down across your lap, or tummy up on a firm surface. Choose the position that's most comfortable for the child and makes it easiest for you to access the rectum.
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    Turn on the thermometer. Most digital thermometers have a clearly labeled button you press to power on the device. Allow a moment or two for it to get set to take the temperature.
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    Hold the child's buttocks apart and gently insert the thermometer. Use one hand to hold the child's buttocks apart and the other to insert the thermometer about .5 inches (1.3 cm) inside. Stop if any resistance is felt.[8]
    • Keep the thermometer in place by holding it between your first and middle fingers. Meanwhile, keep your other hand firmly but gently on the child's bottom to prevent squirming. If your child starts squirming or becomes agitated, remove the thermometer and calm them down. Try again once the child is calm.
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    Once the beep sounds, carefully remove the thermometer. Read the thermometer to determine whether the child has a fever. A temperature of 100.4 °F (38.0 °C) or higher indicates a fever.
    • Call the doctor if your baby has a fever 100.4 °F (38.0 °C) or higher.
    • If the person with the fever is an older child or adult, call the doctor if it's 101 °F (38 °C) or higher.
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    Wash the thermometer before putting it away. Use warm, soapy water as well as rubbing alcohol to cleanse the tip thoroughly.
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Method 4
Method 4 of 5:

Taking Ear Temperature

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    Use a digital ear thermometer. These thermometers are specifically designed for using in your ear and measure your temperature from your ear drum.[9] Choose a thermometer that has plastic covers that go over the tip so you don’t spread any germs.[10]
    • Ear thermometers won’t work on infants or children younger than 6 months since their ears are too small.
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    Stay inside for 15 minutes before taking a reading. Hot or cold temperatures outside could give you an inaccurate reading. Before you take a temperature with an ear thermometer, come inside and wait at least 15 minutes so you get a correct reading.[11]
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    Pull your ear up and back. If you’re taking a child’s temperature just gently pull their ear straight back to widen their ear canal. If you’re taking an adult's temperature, lightly pull up before tugging it toward the back of their head.[12]
    • Earwax can cause an inaccurate reading, so clean your ears if they’re dirty.
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    Turn on the thermometer and insert the tip in your ear. Check the instructions on your thermometer since it may have specific instructions on how to use it. Switch the thermometer on and gently place it in your ear. Don’t use any force or push hard or you might damage your eardrum.[13]
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    Remove the thermometer when it beeps. Follow your thermometer’s specific instructions for taking a temperature reading. You’ll usually have to hold down a button or turn on a switch. Wait for the thermometer to signal you before taking it out of your ear so you can check your reading.[14]
    • Wash or throw away the cover you used so you don’t contaminate anything else.
    • Ear temperatures are usually 0.5–1°F (0.3–0.6°C) higher than an oral temperature.[15]
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Method 5
Method 5 of 5:

Taking Forehead Temperature

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    Use a digital forehead thermometer. Get a thermometer that’s specifically made for your forehead since other models won’t be as accurate. These types of thermometers are a little more expensive than standard thermometers, but you can use them on adults and infants as young as 3 months.[16]
    • Avoid using analog forehead strips since they aren’t as accurate.[17]
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    Place the thermometer’s sensor on your forehead. Turn on your thermometer and press the sensor flush on your forehead. Be careful not to lift or tilt the sensor, or else you won’t get an accurate reading.[18]
    • Make sure you brush your hair out of the way or take off anything that’s covering your forehead.
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    Slide the thermometer toward the top of your ear. Slowly sweep the thermometer straight across your forehead. Be careful not to lift the sensor off of your skin, or you may read an inaccurate temperature.[19]
    • Read the instructions on your thermometer thoroughly since you might not have to move newer models across your forehead.
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    Check your temperature when you reach your hairline. After you reach your hairline, pull the thermometer off of your skin and look at the screen to find your temperature.[20] If you’re an adult, call a doctor if your temperature is over 103 °F (39 °C). If you’re taking an infant’s temperature, talk to a pediatrician if their temperature is over 100.4 °F (38.0 °C).[21]
    • Forehead temperatures typically are 0.5–1°F (0.3–0.6°C) cooler than an oral temperature.[22]
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Expert Q&A

  • Question
    Do I have to do a rectal temperature check on a baby when taking a temperature?
    Luba Lee, FNP-BC, MS
    Luba Lee, FNP-BC, MS
    Board-Certified Family Nurse Practitioner
    Luba Lee, FNP-BC is a Board-Certified Family Nurse Practitioner (FNP) and educator in Tennessee with over a decade of clinical experience. Luba has certifications in Pediatric Advanced Life Support (PALS), Emergency Medicine, Advanced Cardiac Life Support (ACLS), Team Building, and Critical Care Nursing. She received her Master of Science in Nursing (MSN) from the University of Tennessee in 2006.
    Luba Lee, FNP-BC, MS
    Luba Lee, FNP-BC, MS
    Board-Certified Family Nurse Practitioner
    Expert Answer
    Yes, the American Academy of Pediatrics recommends to check a baby’s temperature rectally to get the most accurate reading. But you can also check baby’s temperature on the forehead with a temporal artery thermometer or under the armpit with an axillary thermometer.
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Warnings

  • Always sanitize thermometers immediately after you use them.
    ⧼thumbs_response⧽
  • Call your medical provider or go to the emergency room if your baby has a temperature of 100.4 °F (38.0 °C) or higher.
    ⧼thumbs_response⧽
  • Dispose of old mercury thermometers properly. Even the tiny amount of mercury in a thermometer is enough to do much environmental harm if it is released. Contact your city to learn more about your local hazardous waste disposal protocols. You may be able to bring the thermometer to a designated disposal facility or a local hazardous waste event.
    ⧼thumbs_response⧽
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References

  1. ↑ https://kidshealth.org/en/parents/take-temperature.html
  2. ↑ http://www.babycenter.com/0_how-to-take-your-babys-temperature_11508.bc?page=1
  3. ↑ https://kidshealth.org/en/parents/take-temperature.html
  4. ↑ http://www.healthychildren.org/English/health-issues/conditions/fever/Pages/How-to-Take-a-Childs-Temperature.aspx
  5. ↑ http://www.babycenter.com/0_how-to-take-your-babys-temperature_11508.bc?page=1
  6. ↑ http://www.babycenter.com/0_how-to-take-your-babys-temperature_11508.bc?page=1
  7. ↑ http://www.babycenter.com/0_how-to-take-your-babys-temperature_11508.bc?page=1
  8. ↑ https://www.drugs.com/cg/taking-a-rectal-temperature.html
  9. ↑ https://www.mayoclinic.org/diseases-conditions/fever/in-depth/thermometers/art-20046737
  1. ↑ https://www.drugs.com/cg/how-to-take-an-ear-temperature.html
  2. ↑ https://www.seattlechildrens.org/conditions/a-z/fever-how-to-take-the-temperature/
  3. ↑ https://www.drugs.com/cg/how-to-take-an-ear-temperature.html
  4. ↑ https://www.drugs.com/cg/how-to-take-an-ear-temperature.html
  5. ↑ https://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/in-depth/thermometer/art-20047410
  6. ↑ https://www.mottchildren.org/health-library/tw9223
  7. ↑ https://www.mayoclinic.org/diseases-conditions/fever/in-depth/thermometers/art-20046737
  8. ↑ https://www.seattlechildrens.org/conditions/a-z/fever-how-to-take-the-temperature/
  9. ↑ https://www.mghpcs.org/ipc/programs/committees/Documents/DYK/Temporal_Artery_Thermometry_TAT_DYK.pdf
  10. ↑ https://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/in-depth/thermometer/art-20047410
  11. ↑ https://www.seattlechildrens.org/conditions/a-z/fever-how-to-take-the-temperature/
  12. ↑ https://kidshealth.org/en/parents/take-temperature.html
  13. ↑ https://www.mottchildren.org/health-library/tw9223

About This Article

Luba Lee, FNP-BC, MS
Medically reviewed by:
Luba Lee, FNP-BC, MS
Board-Certified Family Nurse Practitioner
This article was medically reviewed by Luba Lee, FNP-BC, MS. Luba Lee, FNP-BC is a Board-Certified Family Nurse Practitioner (FNP) and educator in Tennessee with over a decade of clinical experience. Luba has certifications in Pediatric Advanced Life Support (PALS), Emergency Medicine, Advanced Cardiac Life Support (ACLS), Team Building, and Critical Care Nursing. She received her Master of Science in Nursing (MSN) from the University of Tennessee in 2006. This article has been viewed 128,916 times.
4 votes - 75%
Co-authors: 20
Updated: February 23, 2022
Views: 128,916
Categories: Thermoregulation | First Aid and Emergency Health Care

Medical Disclaimer

The content of this article is not intended to be a substitute for professional medical advice, examination, diagnosis, or treatment. You should always contact your doctor or other qualified healthcare professional before starting, changing, or stopping any kind of health treatment.

Article SummaryX

To take the temperature of an adult or a child over the age of five, use a multi-use or oral digital thermometer. Before you use the thermometer, use rubbing alcohol to sterilize the tip and rinse it with cool water. Then, turn the thermometer on and insert it under the person’s tongue so that the tip is completely covered. Wait for the thermometer to beep, and then look at the digital display to tell if the person has a fever, which is indicated by any temperature above 100.4 degrees Fahrenheit. The best way to take the temperature of an infant or toddler is with a rectal thermometer. To prepare the thermometer, sterilize it with rubbing alcohol and cover the tip with petroleum jelly to make it easier to insert. Then, place your child on their tummy on a comfortable surface and turn on the thermometer. Hold your child’s buttocks apart and gently insert the thermometer into the rectum about a half of an inch. Once the thermometer beeps, remove it carefully to read the display. If your child has a fever, call your doctor right away. For more tips from our Medical co-author, like how to take an axillary temperature, keep reading!

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