Taking a temperature: What am I measuring?

Taking a temperature: What am I measuring?

When you take a temperature, you are trying to measure how hot your child is inside their body. This is called their 'core temperature'.

Key points to remember about taking a temperature

  • the normal temperature inside your child's body is around 37 degrees Celsius
  • a fever is when the temperature is more than 38 degrees Celsius

When I take my child's temperature, what am I measuring? 

When you take a temperature, you are trying to measure how hot your child is inside their body. This is called their 'core temperature'.

You measure the temperature in places that are closest to the inside temperature. You measure the temperature:

  • inside the mouth (oral), or
  • under the arm (axillary), or
  • in their outer ear canal (tympanic)

Should I measure my child's temperature in their bottom?

In hospital, doctors and nurses sometimes measure temperatures in children's bottoms - they take a rectal temperature. You shouldn't take your child's temperature this way at home.

What is a normal temperature for my child?

The normal temperature inside your child's body is around 37 degrees Celsius. Your child's brain helps control their core temperature and to keep it around that level.

After 3 months of age, body temperature changes with a daily rhythm - rising toward the end of the day before dropping overnight and then slowly coming up to about 37 in the morning.

Young babies are not as good at controlling their temperature as older children.

What temperature indicates a fever in my child?

A fever is when the temperature is more than 38 degrees Celsius. A fever by itself does not indicate whether your child is seriously sick or not.

This page last reviewed 26 November 2018.
Email us your feedback


On this page