High temperature (fever) in adults

What is a high temperature?

Normal body temperature is different for everyone and changes during the day.

A high temperature is usually considered to be 38C or above. This is sometimes called a fever.

Check if you have a high temperature

You may have a high temperature if:

Important: Important

If you feel hot or shivery, you may have a high temperature even if a thermometer says your temperature is below 38C.

Do I need to take my temperature?

You do not need to take your temperature using a thermometer, but you can if you have one.

Make sure you use it correctly to help get an accurate result. See how to take a temperature.

Treating a high temperature

If you have a high temperature, it can help to:

Causes of a high temperature

Many things can cause a high temperature. It's not usually a sign of anything serious.

It's often just caused by your body fighting an infection, such as a cold or flu.

Sometimes it could be a sign of something more serious if your temperature is very high or will not come down.

Information:

Advice for children

This page is for adults. For advice about children, see high temperature (fever) in children.

Page last reviewed: 6 April 2020
Next review due: 6 April 2023