You kiss your child's forehead and feel a hint of heat. Could it be a fever? The back of your hand or your lips clue you in to a fever, but to know for sure, you'll reach for a thermometer.

How you'll take your child's temperature depends on your child's age – by mouth (oral), in the bottom (rectal), under the arm (axillary), or in the ear (otic):

For infants under the age of 2, opt for your baby's bottom or his/her armpit.

For tots between 2 and 5 years of age, your toddler's bottom will still get the most accurate reading, followed by his/her ear or armpit.

Children older than 5 are able to hold a thermometer in their mouth, and this method gives the most accurate reading. Checking temperature in the ear or armpit would be your next-best choices.

Your choice of thermometer will also depend on your child's age and how you've chosen to take their temperature:

Digital thermometers are quick, give an accurate result, and can be used to take oral, rectal, or under-the-arm temperature measurements.

Electronic ear thermometers are simple to use and easy to keep clean, but they are not as versatile, affordable, or accurate as a digital thermometer.

Plastic temperature strips are like a disposable bandage version of a thermometer you press against your child's forehead. While not very accurate, they might be a good option for stowing in the car or in your purse if you ever need a temperature-taking tool in a pinch.

Glass mercury thermometers are no longer a favoured choice, due to potential mercury exposure. Because mercury is an environmental toxin, check with a pharmacist or your doctor to get instructions for proper disposal of old mercury thermometers.

Normal temperatures depend on which method you use:

  • 36.6°C to 38°C (97.9°F to 100.4°F) if measured rectally
  •  35.5°C to 37.5°C (95.9°F to 99.5°F) if measured orally
  •  34.7°C to 37.3°C (94.5°F to 99.1°F) if measured under your child's arm
  •  35.8°C to 38°C (96.4°F to 100.4°F) if measured in your child's ear

No matter which method or thermometer you choose, it's important to take your child's temperature the right way to get the most accurate reading:

How to take a rectal temperature (for infants and children up to 5):

  • Clean the thermometer with soap and cool water.
  • Lubricate the tip with petroleum jelly.
  • Lay your child on his/her back with knees bent. An infant can be on his/her belly across your lap or on a flat surface with your hand placed on your baby's lower back.
  • Slip the thermometer about 2.5 cm (1 inch) into the rectum and hold in place.
  • After 1 minute, remove the thermometer to read the temperature.
  • Repeat the clean-up from step 1.

How to take an oral temperature (for children 5 years of age or older):

  • Clean the thermometer with soap and cool water.
  • Place the thermometer tip beneath your child's tongue.
  • Instruct your child to keep his/her mouth closed while temperature is taken.
  • After 1 minute, remove the thermometer to read the temperature.
  • Repeat the clean-up from step 1.

Tips: Wait for a little while to take your child's temperature after he/she has had anything to eat or drink. Check for gum or candy in your child's mouth.

How to take your child's temperature under his/her arm (for children of all ages):

  • Clean the thermometer with soap and cool water.
  • Remove your child's shirt and slip the tip of the thermometer into the middle of your child's armpit.
  • Tell your child to hold that arm tucked against his/her body while temperature is taken.
  • After 1 minute, remove the thermometer to read the temperature.
  • Repeat the clean-up from step 1.

How to take your child's temperature in his/her ear (for children 2 years of age or older):

  • Check the instructions for your ear thermometer for details on measurement (how long to squeeze the button to get a reading, how far to insert the thermometer, etc.).
  • Apply a clean tip before use.
  • Tug your child's earlobe down and back to open the ear canal.
  • Place the thermometer into your child's ear to the point that the ear canal is sealed off.
  • Take the temperature measurement (instructions may vary).