Pregnancy and baby

How to take your baby's temperature

A normal temperature in children is about 36.4C (97.5F) but this does differ slightly from child to child. A fever is usually considered to be a temperature of over 37.5C (99.5F).

You may be concerned that your baby has a fever if they:

  • feel hotter than usual to the touch – on their forehead, back or stomach
  • feel sweaty or clammy
  • have flushed cheeks

What causes a fever in children?

A fever is relatively common in babies and small children. It can be a sign that the body is trying to fight an infection. When the body’s temperature increases, it’s harder for bacteria and viruses that cause infection to survive.

Fever in children has more information about the illnesses caused by infections, both common and serious, that can cause a fever in children.

Some babies and young children also get a fever shortly after having their routine vaccinations. This should clear up quite quickly by itself. If you’re concerned, speak to your health visitor or GP.

How do I take my child’s temperature?

If you’re concerned that your baby has a raised temperature, the best first step is to check their temperature with a thermometer. This will help you work out whether you need to call a doctor. If you speak to a doctor or nurse on the phone, it will help them make a decision about the type of medical attention your child needs.

Ideally, to get a fast and accurate reading of your child’s temperature, you need a digital thermometer. These are available from pharmacies and most large supermarkets.

Digital thermometers

To find out your child’s temperature, hold them comfortably on your knee and place the thermometer under their armpit (always use the thermometer under the armpit with children under five). Gently but firmly hold their arm against their body to keep the thermometer in place for the time stated in the manufacturer’s instructions (usually about 15 seconds). Some digital thermometers beep when they are ready. The display on the thermometer will then show you your child’s temperature.

Other types of thermometer

Other types of thermometer are available, but may not be as effective as a digital thermometer for taking a baby or small child’s temperature.

Ear (or tympanic) thermometers allow you to take a temperature reading from the ear. These thermometers are quick but expensive, and can give misleading readings, especially in babies, if they’re not correctly placed in the ear.

Strip-type thermometers are held on to the child’s forehead, and are not an accurate way of taking a temperature. They show the temperature of the skin, rather than the body.

Mercury-in-glass thermometers should not be used. They are no longer used in hospitals and not available to buy. They can break, releasing small shards of glass and highly poisonous mercury. If your child is exposed to mercury, get medical advice immediately.

How can I make sure the reading is accurate?

If you use a digital thermometer under your child’s armpit, and follow the manufacturer’s instructions carefully, you should get an accurate reading.

However, there are a few circumstances that could slightly alter the reading, for example if your child has been:

  • wrapped up tightly in a blanket
  • in a very warm room
  • very active
  • cuddling a hot water bottle
  • wearing a lot of clothes
  • having a bath 

If this is the case, allow them to cool down for a few minutes (without allowing them to become cold or shivery), and take their temperature again to see if there has been any change.

What should I do now?

Always contact your GP, health visitor, practice nurse or nurse practitioner if:

  • your child has other signs of illness as well as a raised temperature
  • your baby’s temperature is 38C (101F) or higher (if they’re under three months), or
  • your baby’s temperature is 39C (102F) or higher (if they’re three to six months)

If you need to speak to someone outside normal surgery hours, you can call your GP surgery’s out-of-hours service (if they have one) or NHS 111.

If your child’s temperature is only slightly above normal, and they don’t have any other symptoms, you can help to make them more comfortable. Make sure they get plenty of drinks to avoid dehydration. If you're breastfeeding, then breast milk is best.

Find out more in Treating a high temperature in children.

Page last reviewed: 26/03/2015

Next review due: 26/03/2017

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