When to take your child’s temperature

You can take your child’s temperature as often as you want, but it’s a good idea to take a temperature 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. If your child’s temperature is higher than 38°C, they probably have a fever.

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. 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. Ear thermometers are quick and easy to use, but they can be a little inaccurate.

Digital forehead or temporal artery thermometers
Digital temporal artery thermometers measure the temperature on your child’s forehead.

These are the easiest types of thermometers to use, but they can be inaccurate. It’s better to use a different type of thermometer if you have one.

Other thermometers
Digital pacifier thermometers, fever strips and smartphone apps aren’t recommended because they’re not very accurate.

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 a temperature.

Taking your child’s temperature

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.

Here are more tips to help you take your child’s temperature accurately.

Oral temperatures
You take an oral temperature using a probe thermometer:

• Wait 5 minutes after your child has had a hot or cold drink.
• 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 a blocked nose because of a cold, they might find it hard to breathe with their mouth closed.

You can take oral temperatures in children over 4 years. It’s hard to take an oral temperature in children younger than this, because they can’t always co-operate with you.

Armpit temperatures
You take an armpit temperature using a probe thermometer:

• Place the thermometer in your child’s armpit.
• 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. Unfortunately, it’s also less accurate than an oral temperature reading.

Ear temperatures
You take an ear temperature using an ear thermometer:

• Put a plastic cover over the tip of the thermometer.
• Put the tip gently just inside your child’s ear canal.
• Wait until the thermometer beeps and then check the digital display for the temperature reading.

Digital ear thermometers are fairly accurate, but readings can be affected by small ear canals and earwax.

Forehead temperatures
You take a forehead temperature using a temporal artery thermometer:

• Check that your child’s forehead is dry before starting.
• Gently scan the thermometer across your child’s forehead.
• Remove the thermometer and then check the digital display for the temperature reading.

Your GP or child and family health nurse can show you how to get a fairly accurate reading using a thermometer.

When to see a doctor about fever and high temperature

It’s normal for your child’s temperature to go up and down when they have a fever. Your child’s temperature will 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 aged 0-12 months has a fever, take them to a GP as soon as possible.

If your child aged over 12 months has a fever, take them to a GP if their fever lasts more than 4 days or if you’re worried for any other reason. You should also see a GP if your child:

• looks sicker than before – for example, your child is more pale, lethargic and weak
• has some trouble breathing
• is drowsy
• seems mildly dehydrated, refuses to drink or is weeing less often
• complains of a stiff neck, a mild headache or light hurting their eyes
• vomits or has diarrhoea
• suffers mild pain or discomfort.

If any of these symptoms are severe – for example, your child finds it very difficult to breathe or is unresponsive – or if your child’s condition worsens rapidly, go to a hospital emergency department or call an ambulance straight away.