How to Take a Temperature: Children and Adults

HealthLinkBC File Number: 
Last Updated: 
January 2016

There are 4 ways to take (measure) a temperature:

  • under the armpit (axillary method);
  • in the mouth (oral method);
  • in the ear (tympanic method); and
  • in the rectum/bum (rectal method).

What type of thermometer should I use?

A digital thermometer is best for taking temperatures by the armpit and mouth. Fever strips and pacifier thermometers do not give an accurate temperature. Do not use a mercury thermometer. Mercury is toxic and the thermometer could break.

Speak to a pharmacist if you have any questions when buying a thermometer. A pharmacist can help you select the best type of thermometer for the method you choose to use.

Whichever type of thermometer you use, make sure to clean them (except ear thermometers) with cool, soapy water and rinse off before and after use.

How should I take a child’s temperature?

A child’s temperature can be taken under the armpit, in the mouth, in the ear, or in the bum. Take your child’s temperature whichever way you are comfortable with, as long as it is appropriate for their age. For more advice and detailed instructions on how to take your child’s temperature, speak to your health care provider.

Always wash your hands before and after taking your child’s temperature. For more information on hand washing, see HealthLinkBC File #85 Hand Washing for Parents and Children.

Make sure to read and follow the manufacturer’s instructions each time you use a different type or brand of thermometer.

Axillary method (under the armpit)

The armpit method is usually used to check for fever in newborns and young children. Place the tip of the thermometer in the centre of the armpit.

  • Make sure your child’s arm is tucked snugly (closely) against their body.
  • Leave the thermometer in place for about 1 minute, until you hear the “beep”.
  • Remove the thermometer and read the temperature.

Oral method (in the mouth)

The mouth method can be used for children who are older than 5 years of age. It is not recommended for children younger than 5 years of age, because it is hard for them to hold the thermometer under their tongue long enough.

  • Carefully place the tip of the thermometer under your child’s tongue.
  • With your child’s mouth closed, leave the thermometer in place for about 1 minute until you hear the “beep”.
  • Remove the thermometer and read the temperature.

Tympanic method (in the ear)

The ear method is recommended for children older than 2 years old. Though quick to use, the ear method can produce temperature readings that are too low, even when the manufacturer’s directions are followed.

  • Use a clean probe tip each time, and follow the manufacturer’s instructions carefully.
  • Gently tug on the ear, pulling it back. This will help straighten the ear canal, and make a clear path inside the ear to the ear drum.
  • Gently insert the thermometer until the ear canal is fully sealed off.
  • Squeeze and hold down the button for 1 second.
  • Remove the thermometer and read the temperature.

Rectal method (in the rectum or bum)

The rectal method can be used to check for fevers in newborns and young children. Use a rectal thermometer only if you are comfortable doing so.

  • Cover the silver tip with petroleum jelly (such as Vaseline).
  • Place your baby on their back with their knees bent.
  • Gently insert the thermometer in the rectum, about 2.5 cm (1 inch), holding it in place with your fingers.
  • Leave the thermometer in place for about 1 minute until you hear the “beep”.
  • Remove the thermometer and read the temperature.

For more detailed instructions on how to take a temperature using the rectal method, speak to your health care provider.

After a thermometer has been used to take a rectal temperature, do not use it to take an oral temperature. Make sure that the rectal thermometer is clearly marked so that it is not mistakenly used orally. For example, you could label your rectal thermometer with an “R” and your oral thermometer with an “O”.

How should I take an adult’s temperature?

Take an adult’s temperature by mouth, in the ear or under the armpit. The armpit method is less accurate and is normally only used if the person is extremely drowsy or not clear mentally. Follow the same methods used for taking a child’s temperature.

What is a normal temperature?

The normal temperature range varies, depending on the method you use:

Method Normal temperature range
Armpit 36.5°C - 37.5°C (97.8°F to 99.5°F)
Mouth 35.5°C - 37.5°C (95.9°F - 99.5°F)
Ear 35.8°C - 38°C (96.4°F - 100.4°F)
Rectal 36.6°C - 38°C (97.9°F - 100.4°F)

Temperatures may vary throughout the day, rising as much as 1 degree in the morning and reaching a maximum during the late afternoon. Mild increases may be caused by exercising, too much clothing or bedding, taking a hot bath or being outside in hot weather.

Babies younger than 3 months of age must be seen by a health care provider when they have a fever. During the first 3 months of life, babies are not always able to fight infections, so they need to be seen sooner than older babies and children with fevers.

For babies 3 to 6 months the parents should speak with their health care provider.

When a child is sick with an infection, it is normal to have a fever (temperature higher than 38ºC (100.4ºF)). A fever is part of the normal process of fighting an infection. A fever will not hurt a child. Usually, it goes away after 3 days.

The degree of a fever does not always indicate how serious the illness is, but rather the child’s behaviour, overall appearance and other symptoms such as headache, stiff neck, nausea, and vomiting are generally the most important factors. A fever with other symptoms may mean a more serious illness.

For More Information

For more information, see the following HealthLinkBC Files:

For more information about fever and temperature taking, visit Caring for Kids at

The information in this HealthLinkBC File has been adapted with the permission of Alberta Health and Wellness

Is it an emergency?

If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be a life-threatening emergency. Call 9-1-1 or the local emergency number immediately.
If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.

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