Digital thermometers are placed in the ear or use no-contact readings. They've been designed to make the process of taking a child's temperature less invasive and quicker than old school temperature thermometers
If you have one of these old thermometers kicking around you should no longer use it (they're often filled with mercury) and upgrade to one of the different types of digital thermometer – which type will depend on your needs and your budget.
The NHS also doesn't advise using strip-type forehead thermometers for gaining an accurate reading as they show the temperature of the skin rather than the body.
Ear thermometers (also known as tympanic thermometers) are designed so that they disturb babies as little as possible, even allowing parents to take their baby's temperature when he or she is asleep.
They take a reading after a second or two, using infrared to measure the heat generated inside the ear.
The reading may not be accurate if the thermometer isn't correctly placed in the ear and earwax can also affect the accuracy.
These types of digital thermometer shouldn't be used with newborns as their ear canals are too small.
Even newer to the scene than ear thermometers are infrared no-contact thermometers.
These are usually simply pointed at a child's forehead (usually at a distance of around 5cm, but this can vary from brand to brand) and give a reading very quickly.
They're obviously appealing to parents as you may not even have to disturb your sleeping child to get a measurement.
A great infrared no-contact thermometer should be easy to use and quick to give a measurement.
A back light for seeing readings in the dark and a traffic-light system to indicate a fever are popular features.
Some also have the ability to measure room and surface (ie liquid) temperatures.
Another advantage is that they are hygienic and don't require probe covers like some ear thermometers do, although you must make sure you keep the infrared sensor clean.
Some thermometers can now be connected up to apps on your smartphone or tablet so that you can store a larger database of past readings or connect up to health advice.
All of these types of digital thermometers may need to be used in slightly different ways to obtain accurate readings, so it's important you read the instructions carefully and familiarise yourself with using the thermometer for when you really need it.
For example, some no-contact thermometers require scanning across the forehead and others work by aiming at one point.
Both thermometer and patient should be given time to acclimatise to the environment that they're in if there's been a significant change in temperature.
When using no-contact thermometers, hair must be pushed back off the forehead and any perspiration wiped away.
When buying a digital thermometer, make sure you're handing your money over to a reputable seller. Check the retailer's returns policy and pay attention to customer feedback and reviews. For more details on shopping online safely and arranging refunds for faulty products, see our .
Boots, Argos, Amazon and Superdrug are some of the most searched-for digital thermometer retailers at the time of writing. We’ve included links to these retailers handpicked because of their stock availability, best value price or warranty options.
A fever in adults is generally considered to be 37.8C or higher.