How to tell if you have a fever

How to check if you have a fever, in adults and children

Thermometer for fever
(Image credit: Kelly Sikkema on Unsplash)

One of the symptoms of coronavirus is a fever. But how do you know if you have a fever? What body temperature is considered a fever? We're here to help. 

Before we start, you should not that just because you have a fever doesn't mean that you definitely have coronavirus (coronavirus home test kits are on their way, though). Fever is one of the common symptoms of COVID-19, along with a cough and breathing difficulties. 

A temperature of 38°C or over is generally considered to indicate a fever. If you feel hot to touch on your chest or back, this can indicate you have a fever. You can also take your temperature by using a medical thermometer. 

Ideally, you'd want to pick up one of the best thermometers. However, as with a lot of things right now (including hand sanitizer gel and toilet paper), stock of medical thermometers is looking low, so you might need to branch out a bit. The widget below will pull in available thermometers in your country.

Fevers in children

In babies or children, a normal temperature is around 36.4°C. A temperature of 38°C or above is usually considered a fever. High temperatures are very common in young children (opens in new tab), and usually last only 3-4 days. Furthermore, according to the CDC (opens in new tab), "children with confirmed COVID-19 have generally presented with mild symptoms". 

Check for a fever in children or babies using a thermometer. If the child is under five years old, it is recommended you take their temperature under their armpit using a digital thermometer. Place the temperature gauge under their arm and hold it there for as long as recommended by the manufacturer's instructions (usually around 15 seconds).

If you're taking a child's temperature, make sure there's nothing that would have elevated their temperature for another reason. So, if they've just come out of a warm bath, have been running around, or are wrapped up in a blanket or warm clothes, their temperature might read as higher than normal.

Ruth is currently on secondment as Sleep Editor for Tom's Guide and TechRadar. The role is an extension of her work on T3, where she ran the site's Wellness channel, which includes sleep, relaxation, yoga and general wellbeing. She was also Outdoors editor, reviewing and writing about everything from camping gear and hiking boots to mountain bikes, drones and paddle boards. She has tested more mattresses than her small flat can handle, and has had to implement a one-in-one-out pillow policy, for fear of getting smothered in the night.