WellSpan Home

Fever Temperatures: Accuracy and Comparison

Topic Overview

You can take a temperature using the mouth (oral), anus (rectal), armpit (axillary), or ear (tympanic). But the temperature readings vary depending on which one you use, and you need an accurate body temperature to determine if a fever is present.

Medical research hasn't determined an exact correlation between oral, rectal, ear, armpit, and forehead temperature measurements. Generally, the correlation of temperature results are as follows:

  • The average normal oral temperature is 98.6°F (37°C).
  • A rectal temperature is 0.5°F (0.3°C) to 1°F (0.6°C) higher than an oral temperature.
  • An ear (tympanic) temperature is 0.5°F (0.3°C) to 1°F (0.6°C) higher than an oral temperature.
  • An armpit (axillary) temperature is usually 0.5°F (0.3°C) to 1°F (0.6°C) lower than an oral temperature.
  • A forehead (temporal) scanner is usually 0.5°F (0.3°C) to 1°F (0.6°C) lower than an oral temperature.

It is important to remember:

  • Rectal temperatures are generally thought to be the most accurate for checking a young child's temperature.
  • The manufacturer of the temperature device you use, such as an ear or forehead thermometer, provides information on how to use it. Be sure to read and follow the instructions to obtain an accurate temperature. The information may also include how the results of the device correlate with the results from other methods of taking a temperature.
  • Plastic strip thermometers have some uses, but they aren't recommended for general home use. Unlike oral, rectal, and ear thermometers, plastic strip thermometers measure skin temperature, not body temperature.

When you talk with your doctor about your temperature, be sure to say what method was used to take the temperature.

Temperature comparison table

The temperature comparison table below will give you the range of temperature correlation with the different methods used to take a temperature. For information about taking accurate temperatures in infants and children, see the topic Body Temperature.

To use the table:

  • Find the method that you used to take a temperature.
  • Find the correct temperature range.
  • Look for the temperature range of the other methods that correlates to the method you used. For example:
    • If your 2-year-old child's oral temperature is 101°F (38.3°C), his or her rectal or ear temperature may be about 102°F (38.9°C). Remember, a child has a fever when his or her temperature is 100.4°F (38°C) or higher, measured rectally.
    • If your axillary temperature is 100°F (37.8°C), your oral temperature is about 101°F (38.3°C).
Comparison of temperatures in Fahrenheit by method

Axillary/Forehead (°F)

Oral (°F)

Rectal/Ear (°F)

98.4-99.3

99.5-99.9

100.4-101

99.4-101.1

100-101.5

101.1-102.4

101.2-102

101.6-102.4

102.5-103.5

102.1-103.1

102.5-103.5

103.6-104.6

103.2-104

103.6-104.6

104.7-105.6

Comparison of temperatures in Centigrade by method

Axillary/Forehead (°C)

Oral (°C)

Rectal/Ear (°C)

36.9-37.4

37.5-37.7

38-38.3

37.5-38.4

37.8-38.5

38.4-39.1

38.5-38.9

38.6-39.1

39.2-39.7

39-39.5

39.2-39.7

39.8-40.3

39.6-40

39.8-40.3

40.4-40.9

Credits

ByHealthwise Staff
Primary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency Medicine
Adam Husney, MD - Family Medicine
Kathleen Romito, MD - Family Medicine
Specialist Medical ReviewerH. Michael O'Connor, MD, MMEd, FRCPC - Emergency Medicine
David Messenger, BSc, MD, FRCPC, FCCP - Emergency Medicine, Critical Care Medicine

Current as ofNovember 20, 2017


Are you sure you would like to cancel?

All information will be lost.

Yes No ×

About the provider search

This search will provide you with WellSpan Medical Group and Northern Lancaster County (Ephrata) Medical Group primary care physicians and specialists. If we don’t have a WellSpan Medical Group physician to meet your criteria, the search will expand to include community physicians who partner with WellSpan Medical Group physicians through the WellSpan Provider Network or provide care to patients on the Medical Staffs of WellSpan’s Hospitals.

×

Schedule Your Next Appointment Online with MyWellSpan

Use your MyWellSpan patient portal any time to view available appointments, and pick the date and time that best suits your schedule.

Go to MyWellSpan

New to this practice?

If you don't have a WellSpan primary care provider and would like to schedule a new patient appointment with a provider who is accepting patients, just log into your MyWellSpan account, and go to the Appointment Center section. As you progress through the scheduling process, you will be able to see the offices that are accepting new patients in relation to your zip code. If you are not enrolled in MyWellSpan, go to https://my.wellspan.org, call 1-866-638-1842 or speak with a member of the staff at a participating facility to sign up. New patient scheduling not available at all practices/programs.

Already a patient at this practice?

If you already have a relationship with a WellSpan practice, simply log into your account, and go to the Appointment Center section. As you progress through the scheduling process, you will be able to schedule an appointment with any provider or practice that already counts you as a patient. Online scheduling varies by practice/program.

×