When to take temperature in children

You can take your child’s temperature at any time, but it’s a good idea to do it if your child is:

• unwell and feels warmer than usual
• irritable and crying
• more sleepy than usual
• in pain
• refusing to drink
• vomiting.

The average body temperature for children is about 37°C. A fever is when your child’s body temperature is higher than 38°C.

Types of thermometers

It’s best to check your child’s temperature using a thermometer. Feeling your child’s skin temperature by putting your hand to their forehead isn’t a reliable way of diagnosing a fever.

Most modern thermometers are digital thermometers.

Digital probe thermometers

Digital probe thermometers are the most basic and common types of thermometers.

You can use a digital probe thermometer to take your child’s temperature in 2 main ways:

• Orally – you put the thermometer in your child’s mouth under the tongue.
• Axillary – you put the thermometer under your child’s armpit.

If you plan to check your child’s temperature orally and under their armpit using the same thermometer, make sure to clean it well between each use. You can clean a thermometer using warm soapy water or an alcohol wipe.

Although you can use a digital probe thermometer to take a rectal temperature reading, this isn’t recommended. It’s uncomfortable for your child, and there’s a risk that the tip of the thermometer could damage the lining of your child’s rectum.

Digital ear thermometers

Digital ear thermometers are specially designed for use in children’s ears. These thermometers are quick and easy to use, but they’re not reliable and not recommended.

Digital forehead or temporal artery thermometers

Digital temporal artery thermometers measure the temperature on your child’s forehead. These thermometers are easy to use, but they’re not accurate and not recommended.

Other thermometers

Digital pacifier thermometers, fever strips and smartphone apps aren’t recommended because they can be inaccurate.

Mercury thermometers can poison a child if they break. If you’re using a mercury thermometer, consider replacing it with one of the types of digital thermometers above.

An oral temperature reading using a digital probe thermometer is usually the most accurate way to take temperature.

How to take temperature in children using an oral or armpit thermometer

No matter what kind of thermometer you have, it’s important to carefully read the instructions that come with it before using it for the first time. And if you’re not sure or confident about using the thermometer, your GP, child and family health nurse or pharmacist can show you how.

Here’s a quick guide to taking temperature accurately in children.

Oral temperatures

To take an oral temperature using a probe thermometer:

• Place the thermometer well under one side of your child’s tongue.
• Have your child hold it in place with their lips, not their teeth, and tell them to breathe through their nose.
• Wait until the thermometer beeps and then check the digital display for the temperature reading.

If your child has had a hot or cold drink, wait 5 minutes before taking their temperature.

You can take oral temperatures in children over 4 years. It can be difficult to take oral temperatures in children younger than this, because they might not always co-operate with you.

If your child has a blocked nose because of a cold, they might find it hard to breathe with their mouth closed. In this case, take your child’s temperature under the armpit or in another way.

Armpit temperatures

To take an armpit temperature using a probe thermometer:

• Place the thermometer in your child’s armpit, making sure it touches the skin, not clothing.
• Close your child’s arm over the thermometer, holding their elbow against their body.
• Wait until the thermometer beeps and then check the digital display for the temperature reading.

Taking your child’s temperature under the armpit is usually the easiest way to do it, especially in young children.

An armpit temperature reading will be slightly lower than an oral temperature reading. This is because you’re measuring temperature outside the body, instead of inside.

Medical help: when to get it for a high temperature

It’s normal for your child’s temperature to go up and down if they’re unwell. Your child’s temperature might also be affected by when they last took medicine. The most important thing is to watch your child for signs of serious illness and seek medical attention if needed.

If your child of any age has a weak immune system and a fever, seek immediate medical attention. For example, take your child to your GP or a hospital emergency department.

If your child aged 0-3 months has a fever, seek immediate medical attention. For example, take your child to your GP or a hospital emergency department.

If your child aged over 3 months has a fever, take them to a GP if they:

• have had the fever for 2 or more days
• are having trouble breathing
• are drowsy
• seem mildly dehydrated, are refusing to drink or are weeing less often
• have a stiff neck or a mild headache or light hurts their eyes
• are vomiting
• have a rash
• have a febrile seizure
• have mild pain or discomfort that doesn’t get better with pain medicine.

Also see your GP if your child just doesn’t seem well or seems to be getting sicker and you’re worried.

If any of the symptoms above are severe or if your child’s condition worsens rapidly, go to a hospital emergency department or call an ambulance by phoning 000. If your child finds it very difficult to breathe or is unresponsive, call 000 straight away.