Fever Temperatures: Accuracy and Comparison

Overview

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

Medical research hasn't found an exact correlation between oral, rectal, ear, armpit, and forehead temperature measurements. In general, here's how the temperatures compare:

• The average normal oral temperature is 37°C (98.6°F).
• A rectal temperature is 0.3 to 0.6° C (0.5 to 1° F) higher than an oral temperature. A rectal temperature is generally thought to be the most accurate for checking a baby's temperature.
• An ear (tympanic) temperature is 0.3 to 0.6° C (0.5 to 1° F) higher than an oral temperature.
• An armpit (axillary) temperature is usually 0.3 to 0.6° C (0.5 to 1° F) lower than an oral temperature.
• A forehead (temporal) scanner is usually 0.3 to 0.6° C (0.5 to 1° F) lower than an oral temperature.