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Taking a Temperature (Child) 

Use a digital thermometer to check your child’s temperature. Don’t use a mercury thermometer. There are different kinds and uses of digital thermometers. They include:

  • Rectal. For children younger than 3 years, a rectal temperature is the most accurate.

  • Forehead (temporal). This works for children age 3 months and older. If a child under 3 months old has signs of illness, this can be used for a first pass. The provider may want to confirm with a rectal temperature.

  • Ear (tympanic). Ear temperatures are accurate after 6 months of age, but not before.

  • Armpit (axillary). This is the least reliable but may be used for a first pass to check a child of any age with signs of illness. The provider may want to confirm with a rectal temperature.

  • Mouth (oral). Don’t use a thermometer in your child’s mouth until they are at least 4 years old.

Use the rectal thermometer with care. Follow the product maker’s directions for correct use. Insert it gently. Label it and make sure it’s not used in the mouth. It may pass on germs from the stool. If you don’t feel OK using a rectal thermometer, ask the healthcare provider what type to use instead. When you talk with any healthcare provider about your child’s fever, tell them which type you used.

Below are guidelines to know if your young child has a fever. Your child’s healthcare provider may give you different numbers for your child. Follow your provider’s specific instructions.

Fever readings for a baby under 3 months old:

  • First, ask your child’s healthcare provider how you should take the temperature.

  • Rectal or forehead: 100.4°F (38°C) or higher

  • Armpit: 99°F (37.2°C) or higher

Fever readings for a child age 3 months to 36 months (3 years):

  • Rectal, forehead, or ear: 102°F (38.9°C) or higher

  • Armpit: 101°F (38.3°C) or higher

Call the healthcare provider in these cases:

  • Repeated temperature of 104°F (40°C) or higher in a child of any age

  • Fever of 100.4° F (38° C) or higher in baby younger than 3 months

  • Fever that lasts more than 24 hours in a child under age 2

  • Fever that lasts for 3 days in a child age 2 or older

Oral method

Range of normal: 98.6ºF (37.0ºC), up to 100.0ºF (37.8ºC).

Recommended age: Use this method for children older than age 4 or 5 years, only if they are cooperative.

  1. Take an oral temperature at least 30 minutes after your child has had anything hot or cold to eat or drink.

  2. Place the tip of the thermometer under your child's tongue. Make sure your child does not bite down on the thermometer.

  3. Have your child close their lips gently, without biting on the thermometer.

  4. Have your child keep the thermometer under the tongue until it beeps.

  5. Remove the thermometer and read the temperature on the display.

  6. Clean the thermometer with alcohol or soap and water after each use.

Armpit method

Range of normal: 97.6ºF (36.4ºC), up to 99.0ºF (37.2ºC)

Recommended age: Use this method for children younger than age 4 years or any uncooperative child.

  1. Make sure armpit is dry and your child does not have clothing between the arm and chest.

  2. Place the tip of the thermometer high up in the armpit.

  3. Hold your child's arm snug against his or her body with the thermometer in place until it beeps.

  4. Remove the thermometer and read the temperature on the display.

  5. Clean the thermometer with alcohol or soap and water after each use.

Rectal method

Range of normal: 99.6ºF (37.6ºC), up to 100.4ºF (38.0ºC).

Recommended age: Use this method for children younger than age 4 years

  1. Lubricate the tip of a rectal thermometer with petroleum jelly or a water-soluble lubricant.

  2. Lay your child face down across your lap, or on their side with knees bent toward the chest. Spread buttocks so that the anus can be easily seen.

  3. Hold the thermometer between your thumb and index finger with your hand resting on the buttocks. Slowly and gently insert the thermometer into the anus about 1 inch. The tip should slide in easily. Don't force it. This may cause injury.

  4. Don't let go of the thermometer! Hold it carefully in place until it beeps.

  5. Remove the thermometer and read the temperature on the display.

  6. Clean the thermometer with alcohol or soap and water after each use.

Ear method

Range of normal: 99.6ºF (37.6ºC), up to 100.4ºF (38.0ºC).

Recommended age: Any child older than 6 months

  1. If your child has been outside playing, take the temperature after they have been indoors for at least 15 minutes.

  2. Place a disposable cover on the probe. This is the part that will be inserted in the ear.

  3. Pull the earlobe back slightly, and insert the probe in the ear canal.

  4. Press the On button.

  5. Remove the thermometer after it beeps or otherwise shows it has finished taking the temperature.

  6. Read the temperature on the display.

Temporal artery method

Range of normal: Up to 100.4°F (38.0°C)

Recommended age: Any child older than 3 months. (New research shows that this method may be reliable in infants younger than 3 months.)

  1. Place the thermometer's sensor on your child's forehead, about halfway between the eyebrow and the hairline.

  2. Push the scan button. Keep it pressed down while you slowly slide the thermometer across the forehead toward the top of the ear. Be sure to keep the thermometer touching the skin.

  3. Stop moving the thermometer when you reach the hairline. Let go of the scan button.

  4. Lift the thermometer from your child's forehead and read the temperature on the display.

Online Medical Reviewer: Heather M Trevino BSN RNC
Online Medical Reviewer: Liora C Adler MD
Online Medical Reviewer: Rita Sather RN
Date Last Reviewed: 6/1/2022
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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