How to Use a Thermometer Correctly: Easy Step-by-Step Guide (2024)

  • Categories
  • Health
  • Medical Equipment

Download Article

How to work oral, rectal, axillary, & tympanic thermometers

Explore this Article

methods

1Thermometer Types

2Instructions for Use

3Temperature Reading Interpretation

Other Sections

Tips and Warnings

Related Articles

References

Article Summary

Co-authored byDiana Lee, MD

Last Updated: January 19, 2024References

Download Article

Fevers are reflective of an increase in your body temperature. Mild fevers are often beneficial because they represent the body trying to defend itself against infections. Many germs thrive in a narrow temperature range, so a mild fever prevents them from reproducing.[1] However, high fevers can be dangerous and require medical treatment, so it’s important to get an accurate temperature reading. There are many thermometer types and models available, and we’ll walk you through choosing the best one for you and your circumstances.

Method 1

Method 1 of 3:

Thermometer Types

Download Article

  1. 1

    Use a digital thermometer in most cases. Digital thermometers are accurate and easy to use. They can be used to take a temperature rectally (in the anus), in the armpit (an axillary measurement), or orally (in the mouth).[2]

  2. 2

    Minimize contact with a temporal scanner. Non-contact infrared thermometers allow you to take someone’s temperature without touching them—you simply point the device at their forehead and press a button. However, factors including humidity and perspiration can alter the readings. If you choose this type of thermometer, make sure to follow the manufacturer’s instructions.[3]

    Advertisement

  3. 3

    Try a tympanic thermometer if you’ve been trained on how to use it. Tympanic thermometers measure temperature in the ear canal. However, if they aren’t calibrated or used correctly, they can give inaccurate readings.[4] If this is the only thermometer you have, you can use it, but a digital thermometer is generally a better choice.

    • Avoid using a tympanic thermometer in a child under 3 months of age, as their ear canal may be too small to insert the probe into correctly.[5]
  4. 4

    Steer clear of pacifier thermometers and thermometer strips. While convenient, these methods don’t always produce accurate readings.[6] A digital thermometer is a better option, especially for children.

  5. 5

    Avoid using mercury thermometers. While mercury-filled glass thermometers were a staple in the past, experts don’t recommend using them anymore. The glass can break, exposing you to mercury, which is poisonous.[7] Upgrade to a digital or temporal thermometer for a safer, more accurate way to take a temperature.

  6. Advertisement

Method 2

Method 2 of 3:

Instructions for Use

Download Article

  1. 1

    Take rectal temperatures for the most accurate readings in small children. Have a healthcare provider show you how to take a rectal temperature properly before trying it at home. Cover the tip of a sanitized digital thermometer in petroleum jelly. Position your baby on their back and bend their knees, then gently insert the silver tip of the thermometer 1 inch (2.5cm) into your baby’s rectum. Hold the thermometer in place with your fingers until it beeps (usually about 1 minute). At that point, you can remove the thermometer and check the temperature reading.[8]

    • The American Academy of Pediatrics recommends using a regular digital thermometer to take a rectal (anal) temperature until your child is about 3 years of age.[9]
    • If your child is under 3 months of age, the only way to get an accurate temperature is to take it rectally.[10]
  2. 2

    Measure temperature orally for an easy option. Wash the probe of a digital thermometer with cool soapy water first. Then, place the tip of the thermometer under your tongue toward the back of your mouth. Hold it in place until the thermometer beeps while breathing through your nose. Remove it and read the temperature, then clean the thermometer again.[11]

    • If your child is under the age of 5, it’s unlikely you’ll get an accurate oral reading.
    • Wait 15 minutes after drinking or eating to take a temperature orally for the most accurate reading.[12]
  3. 3

    Try an axillary reading only for screening. Taking your temperature in your armpit provides a less accurate reading than other locations, though it is the most convenient option. Before you start, make sure the armpit is dry. Place the tip of the thermometer into the middle of the armpit, directly against the skin, and hold your arm close to your side. Wait until the thermometer beeps to check the reading.[13]

    • Wait at least one hour after heavy exercise or a hot bath before taking body temperature from the armpit or anywhere else.[14]
    • For better accuracy, take readings from both armpits and then average the two temperatures together.
  4. 4

    Check your temperature using a temporal scanner if you have one. Enlist a helper for this as you can’t take your own temperature accurately with a non-contact infrared thermometer. First, make sure your forehead is clean, dry, and not blocked by your hair or anything else. Ask the person to point the device perpendicularly at your forehead at the distance specified in the manufacturer’s instructions (as this differs between brands). Then, they can simply press the button to get an instant reading.[15]

    • To use a temporal artery thermometer, place the thermometer in the middle of your forehead. Press the scan button and slowly move the thermometer across the forehead toward the ear, making sure it stays in contact with your skin the entire time. When you get the hairline, stop pressing the scan button, and read the temperature.[16]
  5. 5

    Use a tympanic thermometer to take a reading from the ear. Tympanic thermometers sense reflected infrared (heat) emissions from the tympanic membrane (eardrum).[17] Turn on your tympanic thermometer, calibrate it if necessary, and place a disposable cover over the tip. Gently pull the ear back to straighten out the ear canal before inserting the tip of the thermometer into the ear. After about 2 seconds, the thermometer will beep and you can remove it to check the reading.[18]

    • Contrary to popular belief, earwax or ear tubes won’t affect a tympanic reading.
    • Do not use an ear thermometer on an ear that is infected, injured, or recovering from surgery.
  6. Advertisement

Method 3

Method 3 of 3:

Temperature Reading Interpretation

Download Article

  1. 1

    Average: 98.6°F (37.0°C). Additionally, any temperature within the 97.5–99.5°F (36.4–37.5°C) range is considered normal.[19] However, the location where you measure the temperature affects the reading. A normal rectal temperature is 97.9–100.4°F (36.6–38.0°C), a normal tympanic temperature is 96.4–100.4°F (35.8–38.0°C), a normal oral temperature is 95.9–99.5°F (35.5–37.5°C), and a normal axillary temperature is 94.9–99.1°F (34.9–37.3°C).[20] This is because, in general:[21]

    • A rectal (anal) temperature is 0.5-1°F (0.3-0.6°C) higher than an oral temperature.
    • A tympanic (ear) temperature is 0.5-1°F (0.3-0.6°C) higher than an oral temperature.
    • An axillary (armpit) temperature is 0.5-1°F (0.3-0.6°C) lower than an oral temperature.
    • A temporal (forehead) temperature is 0.5-1°F (0.3-0.6°C) lower than an oral temperature.
  2. 2

    Low-Grade Fever: 99.6–100.3°F (37.6–37.9°C). A low-grade fever isn’t usually a cause for concern, as it means your body is fighting off an illness. However, if you have a child under 3 months of age with any fever, contact their pediatrician.[22]

  3. 3

    High Fever: 102°F (39°C) or above. A high fever can be dangerous, so monitor it carefully. Call you doctor if your fever (of any grade) lasts more than 48 hours. If your child is older than 3 months but younger than 1 year, contact their pediatrician for a fever at or above 102°F (39°C).[23] For older children and adults, seek medical attention if you have a temperature over 105°F (41°C).[24] Get emergency care right away if you have a fever and additional symptoms, including:[25]

    • Stiff neck
    • Confusion
    • Vomiting or diarrhea
    • Seizure
    • Irregular breathing
    • Purple spotted rash
    • Persistent sore throat
    • Ear pain
  4. Advertisement

Expert Q&A

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

      Advertisement

      Tips

      • Read the directions included with the thermometer carefully. Although most digital thermometers function in generally the same way, you want to make sure you understand how to use your specific instrument perfectly.

        Thanks

        Helpful1Not Helpful0

      • Prepare the thermometer to read temperatures by pressing the button to turn it on—but make sure the reading is at zero before you slip the disposable plastic sleeve over the probe's tip.

        Thanks

        Helpful0Not Helpful2

      • Digital thermometer sleeves are available anywhere thermometers are sold (grocery stores, pharmacies, etc.). They're inexpensive and usually a one-size-fits-all product.

        Thanks

        Helpful0Not Helpful0

      Show More Tips

      Submit a Tip

      All tip submissions are carefully reviewed before being published

      Name

      Please provide your name and last initial

      Submit

      Thanks for submitting a tip for review!

      Advertisement

      You Might Also Like

      How toOpen a Child Proof Pill ContainerHow toCreate a Home First Aid Kit
      How toUse an Ear ThermometerHow toUse a Band AidHow toIrrigate a Foley CatheterHow toMake a Warm CompressHow toUse a NebulizerHow toUse a StethoscopeHow toRead an MRIHow toEmpty a Catheter BagHow toFill a Hot Water BottleHow to Use a Wrist Blood Pressure CuffHow toMake a Rice SockHow toWalk With One Crutch

      Advertisement

      More References (16)

      1. https://www.aappublications.org/news/2020/11/01/parentplus-thermometers110120
      2. https://www.nhs.uk/common-health-questions/accidents-first-aid-and-treatments/how-do-i-take-someones-temperature/
      3. https://www.aappublications.org/content/30/11/29.2
      4. https://www.healthlinkbc.ca/healthlinkbc-files/take-temperature
      5. https://www.nlm.nih.gov/medlineplus/ency/article/003400.htm
      6. https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/non-contact-infrared-thermometers
      7. https://www.hopkinsmedicine.org/health/conditions-and-diseases/measuring-a-babys-temperature
      8. https://www.nursingtimes.net/clinical-archive/assessment-skills/measuring-body-temperature-06-11-2012/
      9. https://www.nationwidechildrens.org/family-resources-education/health-wellness-and-safety-resources/helping-hands/temperature-digital-and-glass-thermometers
      10. https://www.cedars-sinai.org/health-library/diseases-and-conditions/f/fever.html
      11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819918/
      12. https://medlineplus.gov/ency/article/003400.htm
      13. https://www.cedars-sinai.org/health-library/diseases-and-conditions/f/fever.html
      14. https://medlineplus.gov/ency/article/003090.htm
      15. https://medlineplus.gov/ency/article/003090.htm
      16. https://www.cedars-sinai.org/health-library/diseases-and-conditions/f/fever.html

      About This Article

      How to Use a Thermometer Correctly: Easy Step-by-Step Guide (32)

      Co-authored by:

      Diana Lee, MD

      Family Medicine Physician

      This article was co-authored by Diana Lee, MD. Dr. Diana Lee is a Surgical Retina Fellow. She received her MD from Georgetown University in 2015, did her fellowship at UCLA's Jules Stein Eye Institute, and completed her first residency at USC's Roski Eye Institute. Currently, she is a resident at the Los Angeles County Department of Health Services and a clinical fellow with Associates in Ophthalmology. Her research interests are diverse and include: cataract surgery, dry eye, thyroid eye disease, retinoblastoma and diabetic retinopathy. This article has been viewed 357,303 times.

      2 votes - 100%

      Co-authors: 25

      Updated: January 19, 2024

      Views:357,303

      Categories: Medical Equipment

      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.

      Read More...

      Article SummaryX

      If you're taking an oral reading, place the thermometer at the back of your mouth, under your tongue, and close your mouth. Then, wait until it beeps before taking it out and checking the reading. For an underarm reading, place the thermometer in the middle of your armpit and squeeze your arm against your body to trap the heat there. Wait a few minutes or until it beeps to take the reading. If your temperature is higher than 103 degrees Fahrenheit or your baby’s is higher than 100, you should contact your doctor. For more tips, including how to take a rectal thermometer reading, read on!

      Did this summary help you?

      In other languages

      Spanish

      German

      Russian

      Indonesian

      French

      Thai

      Arabic

      Dutch

      • Print
      • Send fan mail to authors

      Thanks to all authors for creating a page that has been read 357,303 times.

      Reader Success Stories

      • How to Use a Thermometer Correctly: Easy Step-by-Step Guide (33)

        Julia Ligenza

        Apr 30, 2017

        "Helps when you get your period cramps. They hurt you so much, and I hate it so much. "

      More reader storiesHide reader stories

      Did this article help you?

      Advertisement

      How to Use a Thermometer Correctly: Easy Step-by-Step Guide (2024)
      Top Articles
      Latest Posts
      Recommended Articles
      Article information

      Author: Kieth Sipes

      Last Updated:

      Views: 6246

      Rating: 4.7 / 5 (67 voted)

      Reviews: 82% of readers found this page helpful

      Author information

      Name: Kieth Sipes

      Birthday: 2001-04-14

      Address: Suite 492 62479 Champlin Loop, South Catrice, MS 57271

      Phone: +9663362133320

      Job: District Sales Analyst

      Hobby: Digital arts, Dance, Ghost hunting, Worldbuilding, Kayaking, Table tennis, 3D printing

      Introduction: My name is Kieth Sipes, I am a zany, rich, courageous, powerful, faithful, jolly, excited person who loves writing and wants to share my knowledge and understanding with you.