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When taking your baby’s temperature, use a digital thermometer rather than touch alone, as touch can alert you to a high temperature but isn’t fully accurate.
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Signs of a fever include a back or chest that feels hotter than usual, sweating, flushed cheeks, and behaviours that seem out of character for your baby.
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Fever is the body's natural response to fighting infection, and common causes include colds, ear and respiratory infections, flu, chickenpox, tonsillitis, and vaccinations.
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Most fevers can be managed at home and settle within three or four days. Keep your baby hydrated, comfortable and lightly dressed, and check on them throughout the night.
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Never give aspirin to under-16s, never give paracetamol to a baby under two months, and don't undress or sponge your baby down with cold water to try to cool them.
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Seek medical advice immediately if your baby is under three months with a temperature of 38°C or above, if symptoms aren't improving, or if you're worried for any reason.
First things first, although having a baby with a fever can be worrying and stressful, it's important to note that all little ones get a high temperature from time to time. According to NCT, among parents with children aged between six months and five years, over 60% say their child has had at least one.
Fevers in young children usually subside within three or four days. But for your reassurance and their safety, it's important that you know what a normal baby temperature is, and that you can identify a fever to know if your little one is unwell.
Let's run through what a baby's normal temperature should be, cover the causes and signs of fevers in babies, and learn what you should do if your baby has a fever.
What is a baby's normal body temperature?
The normal average body temperature for a baby is around 36.4 - 37.4°C, depending on the part of their body that you're checking.
You can use a digital thermometer to check your baby's temperature if you suspect they have a fever. A high temperature or fever is usually considered to be anything above 37.5°C.
A baby's body temperature is considered low if it goes below 35°C. A temperature this low can potentially cause a sickness known as hypothermia. You should seek urgent medical attention if you're worried that your baby's temperature is dangerously low.
What temperature should a baby’s room be?
A baby’s room should be between 16°C and 20°C, with around 18°C considered ideal. This is the range The Lullaby Trust recommends for safer sleep.
Babies are less able to regulate their own temperature than adults are, so the room around them does more of the work. A room that’s too warm is the greater risk of the two, because overheating is linked to an increased risk of SIDS. Read more about the best room temperature for your baby’s sleep with our guide.
Signs of a fever in a baby
Your little one may have a high temperature or fever if:
- their back or chest feels hotter than usual when you touch them with the back of your hand
- they feel sweaty
- they have flushed cheeks
- they look unwell or are acting out of character
You may also notice that they shiver or have chills when their temperature is on the rise. When it's falling back to normal, you may see them sweating.
What causes fever in a baby?
A high temperature or fever is a natural response that's triggered by the body fighting against an infection.
Little ones sometimes get a high temperature after having their vaccinations. This is normal and means that their vaccination is working. This type of fever commonly goes away quite quickly, usually within two or three days.
Other causes of a high temperature in babies, children and toddlers include common childhood illnesses like:
- ear and respiratory tract infections
- colds
- influenza
- chickenpox
- tonsillitis
Sometimes, a high temperature in babies is associated with more serious illnesses like meningitis, septicaemia, and pneumonia. If you're worried about your little one's health, you should seek medical advice immediately.
Can teething cause a high temperature?
No. Teething does not cause a fever; it may cause a very slight rise in body temperature, but it does not raise a baby’s temperature to 38°C or above. The NHS is clear that a high temperature is not a symptom of teething. Tooth eruption can produce a small temperature increase, but not a clinically significant fever.
If your teething baby has a temperature of 38°C or above, treat it as a fever and follow the guidance on this page, including the red-flag symptoms below. If they’re under three months with a temperature of 38°C or above, seek medical advice immediately regardless of whether they’re teething.
Normal teething symptoms are sore or swollen gums, heavy dribbling, wanting to chew, pulling at an ear, going off food and waking more at night. Want to know more? Read how to ease teething pain with our guide.
Ear or forehead thermometer: which is more accurate for a baby?
Under four weeks old
Use a digital thermometer under the armpit. NICE guidance specifies an electronic thermometer in the armpit for infants under four weeks, and nothing else. Ear thermometers are not recommended at this age, partly because a newborn’s ear canal is very small and awkward to get a reliable reading from.
Four weeks to five years
Use an electronic thermometer in the armpit, ear thermometer or forehead thermometer.
Never use oral or rectal methods on a child under five.
If you’re using an ear thermometer:
- Follow the instructions for your specific model, as probe positioning varies.
- Pull the ear gently back to straighten the canal before inserting the probe.
- Use a clean probe cover every time, as earwax build-up affects readings.
- Wait around 15 minutes after your baby has been lying on that ear, as it will read artificially high.
- Take a reading from the same ear each time if you’re tracking a temperature over several hours.
If you’re using an under-arm digital thermometer:
- Place the tip in the centre of the dry armpit, directly against skin, not through clothing.
- Hold your baby’s arm down against their body for the whole reading.
- Expect a slightly lower number than a core reading, which is normal and is what the ranges on this page are based on.
Using a forehead thermometer is more accurate on sleeping babies or older children that are able to sit still.
What to do if your child has a fever
In most cases, babies with a high temperature can be cared for at home, and their symptoms usually improve over three or four days.
To help you know how to look after your baby when they have a fever, let's cover what you should and shouldn't do...
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Why does my baby feel hot but their temperature is normal?
This is one of the most common things that sends parents reaching for a thermometer at 3am, and most of the time the explanation is straightforward: what you’re feeling on your baby’s skin is not the same as their core body temperature. Here are some reasons why this may be happening:
- When your baby is warm, the blood vessels near the surface of their skin widen to release heat. That’s their body doing exactly what it should, and it makes their skin feel hot to the touch while their core temperature stays entirely normal.
- A prolonged crying episode is physical work. It raises skin temperature noticeably and flushes the face and chest. Check again once your baby has been settled for 15 to 20 minutes and the reading will usually have come down on its own.
- A baby who has been wrapped or in a sleepbag for several hours will feel warm when you unwrap them, particularly across the chest and back. This is normal. It becomes a concern only if they feel sweaty, damp at the back of the neck, or have a flushed face along with rapid breathing, which can indicate overheating rather than a fever.
Other common explanations: your baby has just woken from a deep sleep, has been in a car seat or sling against your body, has been in a warm room or direct sunlight, or has recently had a warm bath or a feed.
How to check it properly
Use the back of your hand on their chest or back rather than their hands and feet, which run cool in healthy babies and tell you very little. Then take a reading with a digital thermometer. If your baby has been crying, wrapped up or in a warm room, wait 15 to 20 minutes and take a second reading before deciding anything.
