Selecting best thermometer for yourself


Selecting best thermometer for yourself

Due to the ongoing COVID-19 pandemic, some medical instruments or devices such as thermometers, pulse oximeters, etc. are becoming necessary to keep handy at home, shop, business area, or work offices also. These devices are very helpful and must have health devices at home to track some health conditions like fever, pulse rate, oxygen saturation in the body and this is need for the time also.

What is a thermometer?

A thermometer is a device or instrument that is helpful to measure the temperature or heat such as the temperature of our body, food, air, or liquid. So when you’re suffering from fever keep it handy.

The temperature is measured in units like Celsius, Fahrenheit, and Kelvin. For measuring the temperature of our body the unit Fahrenheit and Celsius is mostly used and it is designated as symbol °F and °C. The normal temperature of the human body is 98.6°F or 37°C. 1 Degree Celsius is equal to 33.8 degrees Fahrenheit.

3 types of thermometer

There are many types of thermometers available in the market for the measurement of the temperature of different things. But here we are talking about the thermometer which is helpful to measure fever or temperature of the human body and here are details of commonly used, easy to use, and handy thermometers.

(1) Regular mercury thermometer:

This is a stick type glass thermometer containing Mercury marked with Celsius and Fahrenheit unit. This thermometer was widely used and the only option before manufacturing of digital and infrared thermometer.

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  • These thermometers don’t need any batteries and provide accurate results as mercury is highly sensitive to heat.
  • It can be used orally, under the armpit, and in the rectum also.
  • It is durable and very cheap than other thermometers.
  • For personal and family use it is best if you can take proper hygienic care.


  • It contains glass. So care should be taken during washing it as it can break easily.
  • Little children should not use this thermometer orally. Because they may break it accidentally. Thus injury from broken glass may happen and they may also ingest Mercury which is hazardous to health.
  • Marked units on it is difficult to read. You need to learn how to read temperature units marked on it. However, it is not difficult to learn.
  • Every time need to wash it thoroughly after use to prevent infection.

How to use a Mercury thermometer?

You can use the thermometer to take the temperature from the mouth and armpit. However, you can also use it rectally.

Before using wash your hand and thermometer thoroughly to prevent possible infection.

Takedown Mercury at thermometer’s tip part, nearer to first mark of unit.

Put it under your tongue and close your mouth completely. Don’t press it against your teeth to hold it in position. Use your lips to hold it in position. If you are measuring fever from the armpit, keep it in the armpit fossa and press it against the arm and chest perfectly.

Hold it in the position for 1 minute. 2 minutes reading is ideal.

Take out from the position and take the reading. If you have a temperature higher than 99°F then consult your doctor for further advice.

Mercury-free thermometers are also available on Amazon. Have look at it.

(2) Digital thermometer

It is also mostly a stick-like thermometer but different models are also available. It contains a chip in it and uses a heat sensor to detect body heat. It can also be used orally, rectally, or under the armpit.

Digital thermometer
Image credit: Amazon


  • Easy to use. You do not need to take reading manually like a mercury thermometer. In this, temperature reading is shown on the screen.
  • It usually takes less than 1 minute. A beeping sound will ring when the temperature is taken successfully.


  • It needs a battery to operate. If the battery gets drained it may not show accurate results and you need to change the battery immediately.
  • If dropped it gets easily damaged.
  • Only purchase high-quality and best company digital thermometer. Otherwise, it may be useless in a short time.

How to use a digital thermometer?

Before using clean your hand and clean the tip of the thermometer to prevent possible infection.

Check the thermometer is in working condition and the battery isn’t drained.

I suggest using it in the armpit rather than oral use as it cannot be thoroughly washed with water like a mercury thermometer.

Keep in the position till the beep sound rings. It suggests temperature is taken.

The screen will show the temperature reading. If it is higher than normal, then consult your doctor for further advice

Best selling digital thermometer on Amazon with a customer rating of 4.4 out of 5 by 21960 global rating.

(3) Infrared thermometer

It uses infrared energy to detect the temperature of your body. It is also known as a laser thermometer or contactless thermometer, widely famous as a temperature gun.

You can take a temperature reading from the forehead, temporal region, or dorsum of the hands also.

infrared thermometer
Image credit: Amazon


  • It has no contact with the body during use. So no chances of spreading infection like in Mercury or a digital thermometer.
  • Easy to use and provides reading in seconds on the screen, which is easy to read.
  • Some models have advanced measurement functions and memory to track records.


  • It contains a battery. Don’t get the battery drained during use, otherwise it may show false reading.
  • Need to use correctly as advised by the manufacturer. Taking temperature too close or too far away from the skin may not have accurate results. It may not give the correct results if the temperature is taken during the movement of the body.
  • Only purchase best quality and from best reliable company manufacturer. Because low-quality brand thermometer easily run away its accurate results and maybe useless in a short time.
  • Some models are very expensive.

How to use an infrared thermometer?

Power on the thermometer.

When it is ready to use, keep away 3 to 4 cm from the forehead, temporal, or dorsum of the hand to take temperature.

Keep the thermometer steady and don’t move your head to take accurate results.

Press the temperature button on the thermometer.

Within few seconds the device will make a beep sound indicating that the temperature is taken. This will take usually not more than 2 seconds. Note the temperature shown on the screen and if it is higher than normal, take the advice of your doctor.

Best selling ihealth infrared thermometer on Amazon with 4.5 out of 5 by 93524 customer ratings.

Thermometer FAQs

Why mercury is used in thermometers?

Before the availability of infrared and digital thermometers, the Mercury thermometer was widely used and still many doctors also prefer it. However, it is banned in many countries due to hygienic precautions. In this thermometer, mercury is used because it is very sensitive to heat and is the only metal in the liquid form at room temperature. When you have a high fever or an increase in body temperature, Mercury responds quickly and well.

Why thermometer is kept under the tongue?

We use a thermometer when sick. When we have a fever or high body temperature, we need to record how much it is and it is best expressed in the internal organs of the body. So best site to record internal organ temperature is the rectum. But for many peoples and mostly children, it can’t be comfortable. That’s why taking temperature from the mouth by keeping a thermometer beneath the tongue is the best option. Below the tongue, there is more blood flow also.

Which thermometer is most accurate?

If you can take proper hygiene care of the device and if your family members are less or for personal use, a regular Mercury thermometer is best as it gives accurate results.
Digital and infrared high-quality thermometers from reliable manufacturers are accurate and last long. These thermometers are easy to use, especially infrared thermometers to measure temperature for many people.

Is there any temperature difference in oral, rectal, and armpit?

The average normal temperature of the human body is 98.6°F. There may be slight variation in this as many individuals are colder and many are warmer than others. Temperature is measured orally, rectally, and also from the armpit.
When you take the temperature reading from the rectum, it will be 0.5°F to 1°F higher than an oral temperature.
The oral temperature will be 0.5°F to 1°F higher than the temperature taken from the armpit. Because the skin is colder than internal organs like the rectum. This variation is possible while measuring temperature from different sites.

Which thermometer is best for me?

For personal use or use at home with few members like two to four-person in the family, you can buy a regular Mercury thermometer. It costs little than other digital or infrared ones. But you need to take proper hygienic care to prevent infection during use of it. Nowadays, Mercury-free thermometers are also available in this category.
If you have a little more budget, go for an infrared thermometer. When you need to measure the temperature for many persons and quickly then an infrared no-contact thermometer from a reliable manufacturer is best. Because it is easy to use and you can quickly take reading within 2 seconds. So it can be comfortably used at various shops, airports, malls, and all other places where many peoples can be scanned for temperature quickly.

How much time thermometer should be kept in the mouth or armpit?

To record the temperature of the human body the thermometer is kept in the mouth under the tongue, in the armpit, or in the rectum, whichever site is comfortable for you. On all sites, it should be kept for at least one minute. But you can also keep it for 2 minutes. It shouldn’t be kept for more than 2 minutes.

This article is for educational purposes only. Please take advice from your health care experts before taking any action. Thank you. Have a healthy day.

Note: Each product shown here is selected by me. We may earn a commission if you make a purchase using the links included here.

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