The method used to take a child’s temperature depends on their age. Learn how to take temperature by various methods

Published: August 12, 2021 | Updated: November 19, 2024

If you suspect your child has a fever, taking your child’s temperature at home is the best way to know if it’s something that can be managed at home or if you need to seek care as soon as possible. This guide can show you how to take temperature safely and accurately with the right method for your child’s age.

Methods to take temperature

There are a variety of methods of taking temperature as well as thermometers that take them. Temperature-taking methods include:

• Rectal: This method takes temperature in the child’s bottom (rectum)
• Oral: This method takes the temperature from the mouth
• Axillary (Armpit): This method takes the temperature from under the armpit
• Tympanic (Ear): This method takes the temperature from the ear

How to take temperature by age

“The right method varies by age,” said Andrew M. Donovan, M.D., pediatrician with Norton Children’s Medical Group“ Using the preferred method gives you a more accurate reading, which is important for infants, especially those younger than 2 months where any fever is considered a medical emergency.”

Age	Preferred method
Birth to age 3	First choice: Rectal (provides an exact reading) Second choice: Under armpit (to check if fever is present)
Ages 3 to 5	First choice: Rectal Second choice: Ear Third choice: Armpit
Ages 5 and older	First choice: Oral Second choice: Ear Third choice: Armpit

How to take rectal temperature

It can be stressful thinking about taking a rectal temperature, but follow these steps for it to be a relatively easy and safe process.

• Before attempting to take the temperature, sanitize the thermometer with soap and rinse with water.
• Parents can use a lubricant, such as petroleum jelly, on the tip of the thermometer to help with the child’s comfort.
• Place your child either:
  • face-down on your lap or a flat surface (be mindful that it’s not somewhere they could roll off of)
  • face up with their legs bent toward their chest with your hand placed against the back of their thighs
• Insert the thermometer into the opening in their bottom, about ½ to an inch or until the thermometer’s top is in the rectum. Stop if you meet any resistance.
• Hold the thermometer steady while soothing your child as you hold the thermometer in place. Wait until you hear the signal that the temperature reading is complete.
• After hearing the signal, remove the thermometer and make note of the reading, writing it down and include the time of day of the reading.

How to take oral temperature

Taking an oral temperature in older children is a fairly easy process:

• Make sure to wait 20 to 30 minutes after your child has had food or water before taking an oral temperature. There should be no gum, candies or other foods in the child’s mouth during the reading.
• Place the thermometer under the tongue. Ask your child to close their mouth around the thermometer and breathe through their nose. Tell your child to not bite down or attempt to talk while taking the reading.
• Wait until you hear the signal that the temperature reading is complete. At that time, take the thermometer out of the child’s mouth and write down the temperature reading, including the time of day of the reading.

How to take axillary temperature

Taking a child’s temperature from the armpit is an easy and convenient way to get a temperature reading. However, this method doesn’t provide as accurate a reading as the rectal or oral methods. This method can be easier for children who have difficulty holding the thermometer in their mouth. The process includes:

• Take off your child’s shirt and place the thermometer under a child’s armpit — it must be touching skin only; clothing can disrupt the reading.
• Place your child’s arm across their chest, helping to keep the thermometer in place.
• Wait until you hear the signal that the temperature reading is complete. At that time, take the thermometer out of the child’s armpit and write down the temperature reading, including the time of day of the reading.

How to take tympanic temperature

Using a thermometer to take temperature in the ear requires a tympanic (ear) thermometer. You can use that type of thermometer to take temperature via the armpit or within the ear. Make sure to read the manufacturer’s instructions on best use. To take temperature in the ear, parents can:

• Attach a clean cover/probe tip to take the reading.
• Gently pull on the ear, pulling it back. This helps to straighten the ear canal, creating a clear path inside the ear to the ear drum.
• Insert the thermometer until the ear canal is completely sealed off
• Press or squeeze the thermometer as instructed by manufacturer.
• Wait until you hear the signal that the temperature reading is complete. At that time, remove the thermometer from the child’s ear and write down the temperature reading, including the time of day of the reading.