Taking Your Child's Axillary (Armpit) Temperature

A convenient way to take a temperature in a baby or child is by measuring the temperature in the axilla (armpit). This is not as accurate as temperature measured rectally (in the bottom) or orally (under the tongue).

To take an axillary temperature:

• Use a digital thermometer labeled for axillary use. Do not use a glass thermometer that contains mercury, as these aren't safe.

• If your child took a bath or has been bundled tightly for a while, wait at least 20 to 30 minutes to take the temperature.

• Remove your child's shirt and undershirt, and place the thermometer under an armpit. The thermometer tip should touch skin only, not clothing.

• Fold your child's arm across the body to hold the thermometer in place.

• Wait with your child until the thermometer signals that the temperature is ready to be read.

• Remove the thermometer and write down the number on the screen. Include the time of day that you took the reading.

• A reading of 99°F (37.2°C) or above means your child has fever.

Temperatures taken in different ways can give different readings:

Taking temperature by age:

• Babies younger than 3 months: Rectal method is best.

• Babies between 3 and 6 months: Rectal method is best. Temporal artery or axillary method may be used.

• Kids between 6 months and 4 years: Rectal method is best. Ear, temporal artery, or axillary method may be used.

• Kids 4 years or older: Oral method is best if the child can properly hold it under the tongue. If not, rectal, ear, temporal, or axillary method may be used.

Axillary and temporal artery methods can be used at any age (including less than 3 months) to "screen" for fever (get an idea about whether there may be fever). If these show a fever, double check by taking a rectal or oral temperature. 

• You have questions about how to use the thermometer.

• Your child has a fever.

• Your baby is 3 months old or younger and has a rectal temperature of 100.4°F (38°C) or higher or below 97°F (36.1°C).