The 6 Best Thermometers of 2023, Tested and Reviewed

Our Testing Process

With the supervision of medical professionals, the Health team tested 25 digital thermometers in our Lab to see how easily and accurately they took our body temperatures. We evaluated each device for setup, response time, accuracy, ease of use, data readability, and durability since these are the factors we determined to be the most important when choosing between digital thermometers for at-home use.

After getting a baseline temperature taken by a medical professional, all of our testers took their own temperatures with each device twice to measure accuracy. We also repeated this testing process for three different phases—sitting, walking, and running—to further observe the consistency and accuracy of the thermometers.

We considered how easy it was to get started using each thermometer right out of the box, as well as how simple the instructions were to follow and how comfortable the thermometer was to use, especially in the mouth and ear. We also noted how long it took for readings to be measured with each thermometer.

For data readability, we evaluated how large and clear the numbers were on the display, whether it was backlit, and whether the thermometer could store our temperature readings for future comparison. Finally, we assessed each thermometer’s durability by dropping it on the floor from a few different heights (starting at the waistline and going down from there) to see if any of the thermometers suffered obvious cosmetic damage or no longer functioned correctly.

What to Know About Thermometers

Type 

First, you should definitely opt for a digital thermometer, even if it’s a cheap one. According to Marc Helzer, MD, primary care physician with the University of Michigan Health-West, mercury thermometers are no longer recommended because they can break and leak mercury, which is toxic. If you still have one of these, he says you should dispose of it in a hazardous waste collection.

Beyond that, the types of thermometers available differ mainly in location, i.e., where you’ll take your temperature readings. There are three main kinds: 

• oral, rectal, and armpit thermometers
• forehead thermometers
• in-ear (tympanic) thermometers

Oral, rectal, and armpit thermometers are the most traditional type; they usually come with interchangeable tips and disposable covers for sanitary use. Forehead thermometers can be either touch or no-touch but are typically scanned across the forehead or simply held in front of the forehead for a moment, giving a quick reading using an infrared scanner. Tympanic thermometers are usually placed just inside the ear canal and use infrared technology to determine body temperature.

Ease of use 

Generally speaking, a thermometer’s ease of use will come down to how simple it is to unbox the thermometer, skim through the instructions, and receive your temperature results. (A thermometer that’s complicated to operate is going to be annoying to use when you or your family member is sick and cranky!)

But there are ease of use concerns that can vary depending on age; for example, an infant might not be able to hold still for a forehead or ear reading, and older children are likely to resist a rectal one. 

“For newborns up to age four, it is best to take their temperature under the armpit or rectum [while] children older than two can also have their temperature taken by ear,” says Dr. Johnston. “It’s also common to take a temperature orally once a child can sit long enough and they are able to hold a thermometer under their tongue, and most adults use oral thermometers.” 

Dr. Johnston also flags the issue of cleaning and caring for your thermometer. Thermometers with a probe will require cleaning after use, she explains, while infrared thermometers won’t since they’re not used internally.

Accuracy 

It can be hard to tell if your thermometer is giving accurate results unless you’re comparing it to another thermometer, and most of us aren’t spending our sick days conducting thermometer accuracy tests. 

That said, if you repeatedly get very different results on the same person while using the same thermometer in the same location, it’s possible something is off with your device. If it’s worked reliably in the past, you may just need to change the batteries. If it’s always been a bit unpredictable, look for a more accurate replacement.

Data display 

A thermometer that’s accurate but doesn't clearly display your temperature reading won’t be that useful. You need a device that gives you quick, easy-to-read results. 

“When you are looking for a thermometer, you should focus on finding the one that is easiest for you to read and use,” says Srini K. Hejeebu, MD, internal medicine specialist at The University of Toledo College of Medicine and Life Sciences, adding that this will probably be some kind of digital thermometer for the majority of people. 

Look for devices with large, backlit displays so you can see the reading easily in all types of light. Some thermometer displays will also turn green, yellow, or red when the result is ready, so it’s even easier to know if your temperature is normal, slightly elevated, or high. 

Lastly, Dr. Johnston says to make sure the thermometer you purchase is available in Celsius or Fahrenheit, depending on what you use: “Many thermometers have the ability to switch between the two, but you wouldn’t want to end up purchasing a thermometer you aren’t able to read or understand.”

Durability

It’s not always a given that a higher-priced thermometer will last longer than a cheaper one; sometimes, all the technology that gives a higher-priced device its costly price tag makes it more prone to failure. But whatever type you choose, you may want to focus on buying one made in the U.S.

“When purchasing a thermometer online or in a store, beware of retailers from outside the United States,” says Dr. Helzer, adding that the FDA offers guidance on purchasing and selling thermometers since they are considered medical devices (and some of those guidelines were modified during the pandemic).

Ultimately, if you’re really not certain, talk to a physician or pharmacist before making your purchase.

Extra features  

You need a basic thermometer that can take an accurate temperature reading, but you may want one that does more than just tell you what your numerical temp is. 

For example, people with chronic health conditions may appreciate the ability to store and track results over time in their thermometer or even on a separate app. Meanwhile, parents might want to focus on color-coded backlit displays and quiet result alerts (like vibration versus beeping) for those middle-of-the-night temperature readings on sick kids.

Your Questions, Answered

How much should a person expect to pay for a quality thermometer? 

Here’s some good news: you don’t have to spend a lot to get a reliable thermometer.

“You can easily get a very good thermometer for less than $20,” says Dr. Hejeebu. “It’s really not necessary to get a high-priced unit.” 

Dr. Helzer agrees, adding that not only are digital contact thermometers available for a budget-friendly cost, but they also come in a variety of shapes and sizes and are readily available at most grocery stores and pharmacies, making them easy to grab when needed.

How do you know if a thermometer is accurate? 

It’s pretty hard, actually, unless you’re willing to do some experimentation. You can test your thermometer repeatedly on yourself, observing whether your temperature changes significantly each time, even when all other parameters (like your location and activity level) don’t change. 

You can also compare the results of one type of thermometer against another; for example, taking an oral temperature with one thermometer and a forehead temperature with a different thermometer. Keep in mind that these readings will need to be adjusted for their location since some types of temperatures (like oral) are typically lower than other types (like rectal and ear). 

What type of thermometer is the most accurate?

Technically, mercury thermometers are the most accurate, says Dr. Johnston, but they’re not the safest option. Among different types of digital thermometers, a rectal temperature is typically considered to be the most accurate, especially in young children; beyond that, forehead temperatures are the second most accurate, followed by oral and ear, then armpit.

What do thermometer readings mean? 

Most body thermometers will give you a number with one decimal place, such as 98.6. (Some basal body thermometers, often used for tracking fertility, go to two decimal places.) 

It depends on age, time of day, and other factors, but in general:

• a temperature between 97 and 99 degrees is considered normal
• a temperature between 99 degrees and 100.3 degrees is considered a low-grade fever 
• a temperature of 100.4 degrees or higher is considered a fever

However, the type of thermometer you’re using can alter what’s considered a normal reading: An oral reading of 100 degrees or higher may be considered a fever, as is an armpit reading of 99 degrees or higher. It’s important to read the manual that comes with your specific thermometer, so you know how it’s calibrated. The manual should specify what’s considered a normal temperature versus a fever based on the device you’re using.

What is the highest temperature a thermometer can measure? 

Digital thermometers used for reading body temperatures usually can’t go as high as ones designed for cooking. Most of them will max out at 109 or 110 degrees Fahrenheit.

Who We Are

Sarah Bradley has been a freelance writer since 2017, tackling health commerce articles, product reviews, and shopping guides on everything from dry skin moisturizers and wart removers to menstrual cups and toothbrushes for braces. She has personally tested electric toothbrushes and water flossers, so knows what makes a good product stand out from a great one (and really, really wants to tell you about it).