Taking a temperature when your baby, toddler or child has a fever - Mayo Clinic Press (2024)

If your child feels warm or seems sick, taking his or her temperature can help you tell if he or she has a fever. In very young infants — under 2 months — a fever is cause to see your child’s health care provider right away. This is because your new baby’s immune system is still developing. In older infants and children, however, a fever in and of itself generally isn’t cause for alarm, unless it’s combined with other signs and symptoms of illness.

Taking your child’s temperature sounds simple enough, but if you’re new to it, you may have questions. Here’s what you need to know to take your child’s temperature.

Thermometer options

There are several types you can choose from:

• Digital thermometers — These thermometers use electronic heat sensors to record body temperature. They can be used in the rectum (rectal), mouth (oral) or armpit (axillary). Rectal temperatures provide the best readings for infants and toddlers. Armpit temperatures are typically the least accurate of the three measures. Digital pacifier thermometers and fever strips aren’t recommended.
• Digital ear thermometers (tympanic membrane) — These thermometers use an infrared scanner to measure the temperature inside the ear canal. Keep in mind that earwax or a small, curved ear canal can interfere with the accuracy of an ear thermometer temperature.
• Temporal artery thermometers —These thermometers use an infrared scanner to measure the temperature of the temporal artery in the forehead. This type of thermometer can be used even while a child is asleep.

Whatever the method, make sure you carefully read the instructions that came with your thermometer. After each use, clean the tip of the thermometer with rubbing alcohol or soap and lukewarm water. For safety — and to make sure the thermometer stays in place — never leave your child unattended while you’re taking his or her temperature.

Age matters

The best type of thermometer — or the best place to insert the thermometer, in some cases — depends on your child’s age.

• Birth to 2 months — At this age, use a standard digital thermometer to take your baby’s rectal temperature.
• 2 months to 4 years — In this age range, you can use a digital thermometer to take a rectal or armpit temperature. Or you can use a temporal artery thermometer. However, wait until your child is at least 6 months old to use a digital ear thermometer. If you use another type of thermometer to take a young child’s temperature and you’re in doubt about the results, take a rectal temperature.
• 4 years and older — By age 4, most kids can hold a digital thermometer under the tongue for the short time it takes to get an oral temperature reading. You can also use a digital thermometer to take an armpit temperature, or use a temporal artery thermometer or a digital ear thermometer.

How it’s done

Here’s how to take a temperature using the different methods. Be sure to turn on the thermometer before you start.

• Rectal temperature — Turn on the digital thermometer and lubricate the tip of the thermometer with petroleum jelly. Lay your child on his or her back, lift his or her thighs, and insert the lubricated thermometer 1/2 to 1 inch into the rectum. Insert the thermometer slowly and stop if you feel any resistance. Hold the thermometer in place until the thermometer signals that it’s done. Remove the thermometer and read the number.
• Armpit temperature — When you place the thermometer under your child’s armpit, make sure it touches skin — not clothing. While the device reads your child’s temperature, hug your child, keeping the side holding the thermometer against your chest. Keep the thermometer tightly in place until the thermometer signals that it’s done. Remove the thermometer and read the number.
• Oral temperature — Place the tip of the thermometer under your child’s tongue toward the back of the mouth and ask your child to keep his or her lips closed. Remove the thermometer when it signals that it’s done and read the number. If your child has been eating or drinking, wait 15 minutes to take his or her temperature by mouth.
• Ear temperature — Gently place the thermometer in your child’s ear. Follow the directions that come with the thermometer to ensure that you insert the thermometer the proper distance into the ear canal. Hold the thermometer tightly in place until it signals that it’s done. Remove the thermometer and read the number.
• Temporal artery temperature — Gently sweep the thermometer across your child’s forehead. Remove the thermometer and read the number.

When reporting a temperature to your child’s health care provider, give the reading you took and explain which thermometer you used and how the temperature was taken.