The Essential Guide to Baby Thermometers

The Essential Guide to Baby Thermometers

As a parent, it’s hard not to worry when your baby is unwell, particularly if they are showing signs of a fever. Your baby can only give you an indication that something isn’t quite right, so it’s important to be able to decipher if your baby is ill. For that reason, a baby thermometer should be a staple in your medical kit.

There are a variety of thermometers available which measure temperature in different parts of the body. Some thermometers are easier to use, while others can give a more accurate temperature reading, so it’s important to do your research before deciding which baby thermometer is the best option for you. Smart Thermometers allow you to continually monitor your baby’s temperature without disturbing their sleep. To help weigh up your options, here are some of the most common types of thermometers and their pros and cons!

Oral Thermometers  

Oral thermometers are held in the mouth, usually under the tongue, to give you a temperature reading and are generally quite accurate. However, they are not suitable for children under five years and are a better choice for older children. Some places may also suggest a pacifier thermometer for a young baby as they have thermometers built in.

Ear Thermometers

These are a popular choice as they are quick and easy to use. Ear thermometers can be tricky if you don’t know how to insert them correctly, so be sure to read the instructions and learn the right way to use yours.

Forehead Thermometers

Forehead thermometers use an infrared scanner to measure the temperature of the temporal artery on a baby’s forehead. They don’t make contact with the skin so can be less distressing for young children.

Rectal Thermometers

These types of thermometer are the most accurate way to check a baby’s temperature which is very important for newborns. The downside is that they can be uncomfortable and stressful for the child.[1] Look for one that gives a fast reading and is easy to clean, as well as having a flexible tip and safety guard. If you’re worried about using a rectal thermometer, be sure to check with a paediatrician first so they can advise you on how to use it correctly.

Armpit Thermometers

Armpit thermometers take an external temperature reading. To use this type of thermometer, simply hold the thermometer securely under your baby’s armpit, making sure that the thermometer makes contact with the skin and not your baby’s clothing. The benefit of armpit thermometers is that they are an affordable and non-invasive option, however, it can be difficult to hold the thermometer in place and get an accurate reading with a wriggling baby.

Smart Thermometers (App Based)

Smart Thermometers, such as the Nurofen FeverSmart Temperature Monitor, involve a small sticker or wearable patch being placed against your baby’s skin (usually under the armpit). The monitor then syncs to an app on your smartphone, allowing you to monitor your baby’s temperature continuously and accurately over a period of time. Many mums find it useful to make a note of the time and temperature when their baby has a fever; the Nurofen FeverSmart Temperature Monitor can track this for you. This is especially useful during the night as it means you can check your baby’s temperature without having to disturb their sleep. One of the big benefits of the Nurofen FeverSmart is that since it tracks your baby’s temperature continuously, you’ll receive a notification on your phone if your baby’s temperature is too high, giving the assurance that you can attend to your child if they are unwell. It is important to always continue to check on your baby in person throughout the day or night, and to contact your healthcare professional if you are concerned about your baby’s temperature.

Whichever baby thermometer you decide to invest in, look for products with a large screen and a backlit display so that it’s easy to read the result even if it’s dark in the middle of the night, for example. Remember to clean your thermometer after each use and store it away safely for next time.

Always read the label. Use only as directed. If symptoms persist, see your healthcare professional.

Comparison table of most popular thermometers:

Remember that normal temperature varies depending on whether you take an internal or external reading, so it’s important to know what to look for depending on which type of thermometer you use and what part of the body you are taking the reading from. An armpit temperature is approximately 1°C less than core body temperature and 0.5°C less than the oral temperature. However, measurements from different locations on the body should not be compared directly.

The NHS states that a baby’s body temperature should range between 36.4 and 37.5 degrees celsius.[2] Temperature does vary slightly from child to child so it’s a good idea to note down your baby’s temperature when they’re well so that you know what their ‘normal’ body temperature is.[3] A temperature of 38.0 degrees celsius or more in a baby under three months of age, and 38.5 degrees celsius or more in older infants is considered significantly high.[4]  According to the NHS, in general, a temperature above 37.5 degrees celsius is considered to be a fever.* More specifically, a temperature of 38.0 degrees celsius or more in a child under five is considered to be a fever.

Normal temperature ranges for different types of thermometers


Ear thermometer

Temporal forehead thermometer

Oral thermometer

Armpit thermometer

Rectal thermometer

Normal temperature range

36.0 - 38.0 degrees celsius[5]

36.0 - 38.0 degrees celsius[6].


36.0 - 37.8 degrees celsius [7].

below 37.2 degrees celsius [8].

below 38.0 degrees celsius[9].














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