How to Use Baby Thermometer: Complete Guide

How to Use Baby Thermometer: Complete Guide
Last Updated: 05 March 2020

Having a child is, on most days, joyful and exciting. There are a lot of things you can do while getting adjusted and getting to know each other. However, when a baby isn’t feeling well things are not so fun. It can be rather frustrating because they have no way of telling what’s wrong, which makes it harder to help them.

One thing that perplexes a lot of new parents is how to tell whether the child has a fever or not.

Now, before we get down to explaining what temperature is a fever for a baby and how to take a baby’s temperature, we would like to mention a few things.

Many people developed their methods to check if the child “feels hot” without using the baby thermometer. They are using the back of the hand to feel to the forehead or alternatively to touch the neck. However, it is necessary to say that kids can seem warm without an actual increase in body temperature caused by sickness. It is possible that you used too many covers, or the room temperature is too high. Additionally, sometimes a newborn temperature may be slightly elevated because of the vaccines. Therefore, even if you are confident that something is wrong with your little one after you felt that they are warmer than before visiting, the doctor use a basal thermometer.

How to Use Baby Thermometer?

We know that realizing that your child feels feverish can be scary, especially when they are younger than 2 months. Still, panic won’t help. It is necessary to understand that fever is our friend because it is the body’s way to signal that there is a problem that requires your attention.

You probably remember a thermometer with mercury from your childhood. This was the staple of medicine a few decades ago, but now it is recommended to avoid it if possible. If it breaks, the mercury will leak and vaporize, which, if inhaled, can lead to poisoning. You can use any from the plethora of excellent digital options. Our recommendation is to try a basal thermometer as it is the most accurate in our experience.

  • Digital Multiuse Thermometer is possibly the best and simplest when you are learning how to take infant temperature. It can be used as a rectal, oral, and axillary basal thermometer.
  • Temporal Artery Thermometer is quite practical to use with young babies. It reads the temperature by being placed on the side of the forehead
  • Tympanic is used with children older than 6 months. It reads infrared heat waves from the ear.

You can use a digital basal thermometer to take the temperature of your child regardless of their age. They are quite cheap and relatively easy to use, but to be sure what is the proper way to use a thermometer read instructions that came with your specific model.

What is the Normal Body Temperature of a Baby?

The first thing that you need to know is what is the average body temperature for a newborn. You probably heard that the average temperature is 98.6 F or 37 degrees C. This is indeed the average, but it doesn’t mean that it is the same for everyone. Some people are ‘warmer’ than others and the same counts for babies.

It is worth mentioning that safe baby temperature varies between 36.6 degrees Celsius (97.9 degrees Fahrenheit) and 37.2 ℃ or 99℉.

But since the normal baby temperature can vary from person to person, keep in mind that it is best to determine your child’s specific body temperature to be sure when they have they have a fever.

Where to Take Baby Temperature?

So, where to put thermometer when you are taking the temperature of a child? There are three ways you can use a digital basal thermometer or another model of your choice.

  • From birth to three months, the safest is to take the temperature rectally using a basal thermometer. According to the new findings, you can also use a temporal artery thermometer with kids under 3 months old.
  • When they turn 3 months up to 4 years old, it is possible to safely check if the kid is feverish by putting the basal thermometer under the armpit (axillary).
  • After 4 years of age, kids can hold the thermometer under the tongue for a few minutes. But you can also choose another option.

Let’s take a look at detailed explanations for taking the temperature in different ways and what type of thermometer is most accurate.

how to use a rectal thermometer baby

How to Use a Rectal Thermometer Baby?

Here we will discuss how to use a rectal thermometer on a baby. If you want to take the temperature rectally, you can use either a digital basal thermometer or a rectal option. Whichever you choose, know that it has to have a flexible tip so you can easily insert it in your kid’s rectum. If you use a basal thermometer, make sure that you don’t use it in other ways, even if you know how to clean a thermometer. This method provides very accurate readings, and its recommended to use it from birth to 3 years old kids.

  • The first thing you need to do is clean it. You can wash it with soap and water or clean it with cotton with alcohol. Don’t use hot water because it can interfere with the reading.
  • Before inserting, put a bit of lubricant on the tip so it can enter the rectum more easily.
  • Place the child belly down on the table or your lap and keep them still. To make sure they don’t move, put your hand on their lower back.
  • Insert the thermometer gently. Be sure to insert only up to 0.5 to an inch (1.3 -2.5 cm) and hold it in place until you hear a beep.
  • Keep in mind that inserting the basal thermometer deeper can injure the baby’s rectum.
how to use ear thermometer

How to Use Ear Thermometer?

Ear or tympanic thermometers are best to use on children older than 6 months because before that, their ear canals are too small, and the readings probably won’t be accurate. They have a narrow tip so that the basal thermometer can enter the ear with ease. These models read infrared heat waves from the eardrum.

  • Turn on the unit and place the tip in the ear directing it towards the baby’s opposite eye.
  • It usually alerts you if it’s not placed correctly.
  • Depending on the model, you might have to wait a few seconds after inserting, to turn it on to take the temperature.
  • When the reading is finished, it will beep.

How to Take Axillary Temperature?

The simplest way to take a temperature on a child is by putting the digital basal thermometer under the armpit. However, it is not as accurate as other models.

how to take axillary temperature
  • It isn’t recommended to take the temperature this way on children younger than 3 months because it is important to have the most accurate reading
  • Turn on the thermometer
  • Take off the kid’s t-shirt and place the unit under the armpit. If your child had a bath, wait around 15 minutes.
  • The armpit should be dry, so the basal thermometer doesn’t move. Bend your baby’s arm in a way that elbow is against the chest.
  • Entertain the kid while taking the temperature. It may take a minute or two to get the reading.
  • When it is ready, it will beep. Take out the unit and record the reading in baby temperature chart.

Some people are wondering how to use an oral thermometer. Place the basal thermometer gently in a child’s mouth and ask them to close. Leave it for about a minute. After that, you should hear a beep, which means that the reading is ready.

how to use infrared thermometer on baby

How to Use Infrared Thermometer on a Baby?

One of the standard infrared thermometers is the temporal artery or forehead thermometer. They are among the most expensive options. However, they are pretty easy to use. For babies under 3 months, it is recommended to use a rectal model, but if you don’t feel comfortable with it, you can use this option.

  • This thermometer has a flattened tip that you are supposed to put on your kid’s forehead.
  • Turn it on and move it across the forehead while holding down the button
  • When you reach the child’s hairline, you can release the button and stop. You should be able to see the reading on display.

When to Take Toddler to Doctor for Fever?

If she or he has a temperature lower than 102℉ (38.9℃), then they probably won’t need medication unless it makes them uncomfortable.

If the temperature is higher, you should consult your pediatrician to see if it is necessary to bring a child in for an exam.

Keep in mind that if the kids behave normally but have a fever, it is probably just a minor illness, such as cold, and there is no reason to be worried.

When to take toddler to doctor for fever

There is probably no reason to take the kid to a doctor if she or he:

  • Eats and drinks well
  • Wants to play
  • Reacts to everything around
  • Has normal skin color
  • Looks better when the temperature lowers

Keep in mind that a lot of children refuse food when they don’t feel well. If they drink and urinate regularly, this shouldn’t be cause for concern.

Very high temperature, greater than 107℉ (41.6℃) when taken rectally that doesn’t go come down with medication, is pretty worrisome.

What Causes Fever in Toddlers?

A plethora of infections can cause fever in children. The most common are viral or bacterial infections of the respiratory system or other organs. Other causes can be related to the use of medication, heat exposure, allergies, or in rare cases, inflammatory diseases.

What Temperature is a Fever for a Baby?

As we already mentioned, the average temperature for babies and children is about 97.8 ℉ or 36.6 ℃ with slight variations. If the kid’s temperature is 100.4℉ or 38℃, it is considered a fever. Use a basal thermometer to make sure you got the right reading.

How High Can a Fever Get?

In theory, fever can go very high, even above 107℉ or 41.6℃, but this is quite rare. Some people think that fevers that go over 104℉ (40℃) are dangerous. The fact is that only temperatures that go over 108℉ or 42℃ are super hazardous because they can cause brain damage. However, it is infrequent for body temperature to go that high.


In the end, we would like to tell you once again that it is better to use a basal thermometer to check your child’s temperature before you rush to the hospital because she or he feels warm. There are plenty of best thermometer options that you can buy, and as you can see, there are relatively simple to use. Before we leave, we want to invite you to revisit us because investigated plenty of interesting and useful topics, such as what is the best way to dry a thermometer.

how to
Share your thoghts
Please fill required fields
Please fill required fields
Please fill required fields