Fever is the body's natural response to infection and isn't an illness on its own. But in babies, what a fever means changes a lot with age. In a baby under 3 months, a temperature of 38°C (100.4°F) or higher is an emergency and needs to be checked without waiting, even if the baby looks well. In older babies, the baby's overall condition matters as much as the number.
Where you take the temperature also affects the result. A rectal reading gives the most accurate result in babies. An underarm reading is easier but usually reads about half a degree Celsius lower. Ear and forehead thermometers are handy but can be less reliable in young babies. Noting where you took the reading helps you give your doctor accurate information. Don't use a mercury thermometer.
Logging readings with their times for a feverish baby makes it easier to see how the fever is changing. Doctors usually ask when the fever started, how high it got and what other symptoms came with it. Instead of trying to remember readings taken through the night, you just look at the log. Noting symptoms such as vomiting, diarrhea, rash, cough or drowsiness also helps judge how urgent the situation is.
What you can do
- Log temperature with the time and method: underarm, rectal, ear or forehead.
- Shows a status label for your baby's age: normal, high fever or emergency.
- Under 3 months, 38°C (100.4°F) or higher triggers an emergency alert and call button.
- Also gives a hypothermia warning for low body temperature.
- A temperature chart shows the normal range and the 38°C fever line.
- Get an AI triage review based on symptoms such as vomiting, diarrhea or rash.
How to use it
- Choose the measurement method and enter the thermometer reading.
- Enter the time, or leave it blank to use the current time.
- Act on the status label and any alert that appears.
- Follow how the fever changes on the chart and daily log.
Frequently asked questions
What temperature is too high for a baby?
It depends on your baby's age. Under 3 months, 38°C (100.4°F) or higher is always an emergency. Between 3 and 6 months, 39°C (102.2°F) or higher should be checked right away. At any age, see a doctor without waiting for 40°C (104°F) or higher. In older babies, overall condition matters as much as the number: lethargy, trouble breathing or refusing feeds need attention.
What is the best way to take a baby's temperature?
In young babies, the most accurate result comes from a digital thermometer used rectally. An underarm reading is easier and can be used for screening, but it usually reads about half a degree Celsius lower. A high underarm reading can be confirmed rectally. Ear and forehead thermometers are handy but less reliable in newborns. Don't use a mercury thermometer.
Why is a fever in a newborn an emergency?
In the first 3 months the immune system isn't mature yet, and serious infections can progress quickly even when the baby looks well. At this age, fever can be the only sign of conditions such as a urinary tract infection, a blood infection or meningitis. That's why a temperature of 38°C (100.4°F) or higher in a baby under 3 months means going to the emergency room right away instead of waiting at home.
How do I bring down my baby's fever?
First consider your baby's age and overall condition: if a baby under 3 months has a fever, go to the emergency room without trying to bring it down at home. For older babies, remove extra clothing, keep the room cool and keep feeding so they get enough fluids. Always ask your doctor or pharmacist about fever medicine and the dose. Sponging with alcohol or cold water is not recommended.