What Counts as a Fever?

A true fever depends on where the temperature is taken. In general:

• rectal, ear, or forehead temperature of 100.4°F or higher
• oral temperature of 100°F or higher
• armpit temperature of 99°F or higher

If your baby is under 3 months old and has a fever, call right away.

Best Temperature Methods by Age

Forehead Temperature

Digital forehead thermometers are simple to use and are the next most accurate option after rectal temperatures. They can be a very practical choice for babies and children, especially when you need a quick reading.

Make sure you follow the thermometer instructions carefully, since placement and scanning technique can affect the reading.

Ear Temperature

Ear thermometers can be accurate when used correctly, but they are not recommended before 6 months of age because the ear canal is too small for reliable readings.

• use only in children 6 months and older
• place the thermometer exactly as directed
• ear wax or poor positioning can affect the reading

Oral Temperature

Oral temperatures can work well in older children who can hold the thermometer under the tongue properly and keep their mouth closed during the reading.

• best for children who can cooperate well
• place the thermometer under the tongue toward the back of the mouth
• have your child close their mouth and keep it there until it beeps

Armpit Temperature

Armpit temperatures are the least accurate, but they can still be helpful as a quick screening method at any age.

If the armpit temperature suggests fever or if your child seems truly sick, it is often a good idea to confirm with a more accurate method.

More Fever Help for Parents

Need Help Checking Your Child’s Temperature?

Dyson Pediatrics helps Tucson families with fever concerns, temperature questions, and when-to-call guidance for babies, children, and teens.