Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.
Fever Temperatures: Accuracy and Comparison
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).
Current as ofJune 26, 2019
Author: Healthwise Staff
Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Adam Husney, MD - Family Medicine
Kathleen Romito, MD - Family Medicine
H. Michael O'Connor, MD, MMEd, FRCPC - Emergency Medicine
David Messenger, BSc, MD, FRCPC, FCCP - Emergency Medicine, Critical Care Medicine
Current as of: June 26, 2019
Author: Healthwise Staff
Medical Review:William H. Blahd, Jr., MD, FACEP - Emergency Medicine & Adam Husney, MD - Family Medicine & Kathleen Romito, MD - Family Medicine & H. Michael O'Connor, MD, MMEd, FRCPC - Emergency Medicine & David Messenger, BSc, MD, FRCPC, FCCP - Emergency Medicine, Critical Care Medicine
To learn more about Healthwise, visit Healthwise.org.
© 1995-2019 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.