How to Take a Child's Temperature – Tips from a Nurse

October 22, 2019
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Mother checking her sick sons temperature

Flu season is just around the corner. Sometimes taking your child’s temperature is the only way to know if they are healthy or sick.

“Temperature tells us a lot about children,” said Teresa Connolly, RN, clinical nurse educator at Baystate Children’s Hospital. “Getting an accurate temperature reading is crucial in knowing if your baby has an illness.”

Every child is different

When taking a temperature, you’re measuring the core temperature of your child’s body. The core temperature refers to a measurement of the internal temperature around the abdomen and the chest. In a healthy child, the thermometer should read around 98.6 degrees. However, every child is different and temperatures can vary slightly.

If your child’s temperature is much higher, there are a few things it could be. One reason is they may be too bundled up. Try taking off a few layers, waiting a while and taking their temperature again. If they are registering a fever after that it may mean that a bacteria or a virus is present.

“It’s important to observe your child because every child is different. However, if your child is warm to touch and irritable that usually means they have a fever,” Connolly said.

Connolly knows first-hand the importance of getting an accurate temperature. She offers some tips on getting the most accurate reading.

Best tool for the job

When taking a child’s temperature it helps to use an updated digital thermometer.

The old glass thermometers have mercury in them, which is toxic and can pose a hazard to your child. Plus, the glass ones are fragile and can easily break.

Digital thermometers also come standard with a notification alarm that tells you when the temperature has been recorded.

Methods of taking temperature

There are five ways to take a child’s temperature. From the least invasive to the most invasive they are:

  • Axillary in the child’s armpit
  • Temporal artery, where a device scans across the forehead and behind the ear. While it’s not as invasive as some of the other methods, its accuracy can easily be compromised by the environment.
  • Tympanic, in which the temperature is taken in the child’s ear. This method is accurate but it requires a specific technique which can be difficult to for parents to do at home.
  • Orally, in the child’s mouth
  • Rectal. This method is considered to be the most accurate and is the pediatric gold standard method for taking temperature. It is the most invasive method and should be reserved for younger children.

So what’s best for my child?

With some methods being more invasive and accurate than others, it’s important to know which method works best for you and your child. Of the five methods mentioned above, three tend to be preferred by pediatricians.


This method gives the most accurate reading. If you choose this method, be sure to use an alcohol swab to clean the thermometer before and after each use. Label the thermometer so it isn’t used for any other purpose. After that you want to use a water soluble lubricant to lubricate the thermometer, then place it in to the anus.

For an infant you want to put it in no more than half an inch, and about one inch in for an older child. Laying the child on their side works best for older children. For an infant, you can put the child on his or her back and bring their legs up, just like when changing a diaper. You can also put them on their belly on your lap or a safe, flat surface. Try them all to see which one work best for your child.


Under the child’s armpit is good for infants and children up to about 3 years of age.

To take your child’s temperature with this method, first you want to expose the child’s armpit. Then put the thermometer in their armpit and hold their arm close to the body until the temperature has been recorded. Keep in mind that an axillary temperature is taken on the exterior of the body, so it will register one degree less than your child’s actual core temperature or rectal temperature reading. Adjust as needed to get the true temperature.


When taking a child’s temperature orally, be sure it’s placed in the sublingual pocket, the area of the mouth where the base of the tongue meets the bottom of the mouth. Hold it there until the device indicates the temperature has been recorded.

The child must be developmentally mature enough to use this method. It’s best used on children who are 3 years of age or older, depending on the developmental stage of the child.

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