Taking your child's temperature can help you know if they have a fever. For most kids, you can take an axillary (under the armpit) temperature with a digital thermometer.

Take your child's temperature with a digital thermometer labeled for axillary use. Follow the instructions that came with the thermometer. In general: 

1. Clean the thermometer before use. You can wipe it with rubbing alcohol on a cotton pad or wash it with soap and water then rinse with cool water.
2. Remove your child's shirt. Wipe the armpit dry, if needed. Place the thermometer under the armpit. The thermometer tip should touch skin only, not clothing. 
3. Fold your child's arm across the body to hold the thermometer in place.
4. Wait with your child until the thermometer signals that the temperature is ready to view.
5. Remove the thermometer and write down the number on the screen. Include the time of day that you took the reading.
6. Turn the thermometer off.
7. Clean the thermometer with either rubbing alcohol or soap and water. 

Reminders:

• An axillary temperature of 99°F (37.2°C) or greater means your child has a fever.
• Wait 20–30 minutes after your child has had a bath to take the temperature. 
• Never use a glass/mercury thermometer. They can break and cut your child and expose them to mercury (a harmful chemical).
• Although an axillary thermometer is easy to use and can be used on children of any age, it doesn't give the most accurate temperature. Check with your health care provider about whether you should be using a rectal (in the bottom), temporal (forehead), or oral (in the mouth) thermometer instead.

• You have questions about how to use the thermometer.
• Your child has a fever of 99°F (37.2°C) or greater. If your child is younger than 3 months old, your health care provider may ask you to get a more accurate temperature with a rectal thermometer.