are digital thermometers more accurate than mercury

Are digital thermometers more accurate than mercury? If you are like most people, you may have thought about it several times.

No doubt, keeping a good medical thermometer on hand at home might be quite useful.

After all, knowing for sure if someone has a fever allows you to take the necessary next steps in their care.

But, ultimately, it all depends on how accurately your thermometer can work.

And that is when you have to choose between mercury and digital thermometers. But, are mercury thermometers accurate?

Digital thermometers are considered accurate due to their sensors, but the quality of those sensors and other factors may make them a bit less accurate than mercury. 

Are Digital Thermometers More Accurate than Mercury?

mercury or digital thermometer

To understand the accuracy of different thermometers, you should know how your thermometer functions like any other household appliance.

Some are better at detecting temperatures than others, and not all types function in the same manner.

But ultimately, most people will have to choose between mercury and digital thermometers. 

More about Mercury Thermometer

Since its invention in 1748, mercury thermometers have reliably measured temperatures to within a few degrees. 

Mercury thermometers are used to take readings because of the mercury contained within the glass. 

It has even been proven scientifically that they are often more reliable than their digital counterparts.

It is worth mentioning that mercury thermometers, previously the most popular, are now discouraged due to the risk of harmful mercury release in the event of a break

More about Digital Thermometers

more about digital thermometers

Electronic sensors in digital thermometers provide precise temperature readings, which are then displayed on a readout. 

These sensors provide very precise temperature measurements to within 0.06 degrees Celsius.

The use of digital and mercury thermometers in a hospital setting has been the focus of a clinical trial.

There is no statistically significant difference between the average accuracy of different types of thermometers, as shown by both laboratory and clinical research.    

Yet, a digital thermometer’s accuracy might change based on elements including the device’s build quality and the sensor it employs.

Fact: Getting a digital thermometer from a trusted brand and using it according to the manufacturer's recommendations offer the most reliable results. 

The Rise and Fall of Mercury and Digital Thermometers

Accurate temperature readings can be obtained via mercury thermometers, which can be used orally, rectally, or subcutaneously.

 A mercury thermometer is convenient because it does not need batteries and can be used immediately. 

Why Do People Avoid Mercury Thermometers?

why do people avoid mercury thermometers

The issue is that they are made of glass and can break easily, exposing you to poisonous mercury.

A broken mercury thermometer poses the additional risk of injury from shards of glass.

Because of this, you should not just throw them out; rather, you should follow the required procedures for disposal.

Mercury thermometers are not only notoriously tricky to read, but they also need to be left in the same spot for three minutes in order to provide an accurate reading. 

The Popularity of Digital Thermometers

the popularity of digital thermometers

Digital thermometers have electronic heat sensors and can be placed in the mouth, rectum, or armpit to record body temperature.

These days, you can get a precise reading of the temperature in less than a minute with the help of a digital thermometer, which is a true technological miracle.

Of course, there are limitations and subtleties to consider with any instrument.

Digital thermometers continue to be a trusted method of temperature measurement.

Remember that different applications may produce slightly different results.

Fact: The temperature measured under the arm is typically lower than that taken orally, but rectal thermometers produce more accurate results. 

Are Digital Ear Thermometers more Accurate than Mercury?

accuracy of digital ear thermometer

Tympanic thermometers are the superheroes when it comes to using digital thermometers.

Infrared technology allows for rapid and precise measurements of ear canal temperature. 

The Shortcomings of Digital Ear Thermometers

Digital ear thermometers are highly efficient, but they are not without their flaws, as is the case with any hero.

For instance, they are not advised for use because of the small size of a newborn’s ear canal.

In addition, it is crucial to get in the right position for reliable outcomes, and impediments like earwax can alter the results.

Thermometers sometimes will not fit comfortably in curved or very narrow ear canals.

Despite these drawbacks, tympanic thermometers are nevertheless a useful instruments for detecting body temperature. 

An Important Consideration

Since the emergence of COVID-19, however, digital thermometers have fallen out of favor because of fears that they can spread the virus through casual contact. 

This is because of the tight quarters necessary while using them in the mouth or armpit, which might lead to the spread of the infection.

Fact: Parents love tympanic thermometers because they eliminate the need for rectal measurements and still deliver accurate results, even in young children. 

More About Using Digital Thermometers Accurately

more about using digital thermometers accurately

To get an accurate reading when taking a temperature orally with a digital thermometer, you have to follow certain guidelines.

For starters, keeping the mouth closed and positioning the thermometer’s tip under the tongue is important.

On the other hand, rectal readings are frequently considered the most accurate for newborns and small children, while being somewhat unpleasant.

Food and drink temperatures can also affect the accuracy of oral reading, so it is best to wait at least 15 minutes after eating or drinking before getting one. 

An Important Consideration

Keep in mind that rectal and oral temperature readings should be taken using different thermometers to prevent cross-contamination.

You might need to buy two thermometers for this purpose, each of which should be properly marked.

Fact: Remember that digital thermometers' batteries die eventually and need to be replaced, so be sure to have spare batteries on hand and learn how to swap them out. 

Factors Affecting the Accuracy of Digital Thermometers

While modern digital thermometers may be a bit more reliable and accurate than mercury, many factors affect the outcome.

For instance: 

Sensor Quality and Type

 A digital thermometer’s sensor is the most important part.

The sensor is responsible for monitoring the environment and translating any changes it senses into electrical signals that can be read off the display.

sensor quality and type

The sensor quality and type greatly affect how precise a thermometer reads.

Better results can be obtained from measurements taken with a high-quality, well-calibrated sensor. 


Calibration of digital thermometers is necessary to maintain accuracy.

Calibration entails bringing the thermometer into agreement with some sort of established norm or reference temperature.

The thermometer’s accuracy relies on regular calibration to ensure reliable readings.

Fact: A thermometer's readings might become erroneous if it loses its calibration over time. 

Average Outside Temperature

average outside temperature

Digital thermometers can be inaccurate if the surrounding temperature is outside of the manufacturer-recommended range.

For this reason, it is crucial to keep the thermometer within its safe operating range and to keep it out of direct sunlight and high temperatures. 

Measuring Speed

 A digital thermometer’s response time is the amount of time it takes for the device to show a temperature measurement after being placed in contact with an object.

In general, a quicker response time suggests a more reliable thermometer.

The delayed response time of some digital thermometers can cause inaccurate readings. 

The Battery Status

the battery status

Battery power is essential for digital thermometers, and it can make them slightly less desirable than mercury thermometers.

The thermometer’s accuracy can be affected by the battery’s voltage.

Low battery voltage can cause the thermometer to malfunction, giving you false readings.

Because of this, it is essential to routinely replace the batteries to maintain accurate readings from the thermometer. 

Correct Positioning

Most digital thermometers have a recommended measuring distance based on the type of object being measured.

Incorrect readings can occur if the thermometer is too far away or too close to the measured object.

Hence, it is crucial to keep the thermometer at the advised distance. 

Infrared Detection

infrared detection

Modern digital thermometers employ infrared technology, which usually delivers accurate results.

However, the accuracy of a thermometer can be compromised by the ability of some substances to absorb infrared radiation.

Shiny items, like metal or glass, can reflect infrared radiation and skew results.

So, you have to bear it in mind to properly interpret the results of an infrared thermometer


Are digital thermometers more accurate than mercury?

Apparently, mercury thermometers are quite accurate, but modern digital thermometers with highly advanced sensors are more capable of delivering accurate results.

But, many factors can lower the accuracy of digital thermometers. Therefore, you should opt for a thermometer made by a reliable brand.

If it comes from a popular brand, chances are they have tested and calibrated it properly to take accurate readings.