The 8 Best Thermometers for At-Home Use, Tested and Reviewed

The Experts

• Maryellen Flaherty-Hewitt, MD, FAAP, Interim Section Chief of General Pediatrics Yale Medicine
• Bradley Katz, MD, PhD, professor at the University of Utah Medical Center and CEO of Axon Optic
  

How We Tested

The Verywell Health team spent eight hours in the Verywell Testing Lab and an additional six months at home testing 25 thermometers to find the best ones. We picked our top thermometers based on the following criteria:

• Ease of setup: We noted how easy it was to set up each thermometer, how intuitive the process was, and how many components (i.e. batteries, Bluetooth, app) were needed to be able to properly use each product.
• Response time: We judged how quick and seamless the process was and paid attention to how long it took to get our results. We also noted if the response time matched what the instructions claimed. Then we recorded if the thermometer told us via light or sound that the reading was ready. 
• Consistency of results: We tested the thermometers throughout different periods of the day to account for hormonal changes, shifts in environments, and other internal and external factors that can impact the consistency of the readings. Because temperature can fluctuate throughout the day, we opted to rate each thermometer for consistency of results rather than reading accuracy.
• Ease of use: When operating the thermometer we paid close attention to whether or not all features of each product were easy to use, and how easily we were able to get accurate temperature readings.
• Data readability: We made note of how many users the thermometer tracked, the legibility of the physical reading, and whether you could convert the thermometers from Celsius to Fahrenheit and vice versa.

The Different Types of Thermometers (And When to Use Them)

There are different types of thermometers that target different areas of the body to get your temperature readings, such as oral, tympanic, temporal, and rectal areas. According to Dr. Katz, rectal thermometers are considered to be the most accurate because they check internal body temperature and are less likely to be influenced by drinking cold or hot drinks, or fluctuating temperatures. However, in practice, oral thermometers are most commonly used among adults. Rectal thermometers are more widely used among children or patients in a hospital setting, Dr. Katz adds. The different types of thermometers are:

• Oral: thermometers which read temperature from the mouth and are best for use from ages 4 and up
• Tympanic: thermometers which read temperature from the ear and are best for use from ages 6 months and up
• Temporal: thermometers which read temperature from the forehead and are best for use from 3 months and up
• Rectal: thermometers which read temperature from the anus or anal canal and are best for use from birth to 3 years old
• Axillary: thermometers that read temperature from the armpit

Helpful Additional Features to Look For

When looking for a thermometer, Dr. Katz recommends people look for a thermometer that’s easy to read and use and that has the quickest (most accurate) response tunes possible. Beyond the temperature reading capabilities, some thermometers have additional features. Fever indicators—a system that tells you if the fever is normal, mild, or high—are popular on many of the digital thermometers we tested and can provide helpful guidance on when to seek medical attention. Smartpone apps are also helpful for tracking and keeping record of temperature history—many "smart" thermometers include these, but sometimes they can complicate the otherwise simple process of taking a temperature reading.

What Type of Thermometer Is Most Accurate?

Dr. Katz says that digital rectal thermometers are the most accurate at measuring core temperature. That’s because they measure the internal body temperature by insertion, and the reading is less likely to be influenced by external factors, such as drinking hot or cold beverages and environmental temperatures. However, rectal thermometers are predominantly used to take temperatures of infants and toddlers up to 3 years old.

For adults, oral thermometers can give accurate and dependable results—just make sure you use them properly, including watching what you eat or drink prior to taking your temperature. Taking a reading shortly after you've eaten something hot or cold can throw off the reading.

Why Trust Verywell Health

Receiving her master’s degree in public health in 2020, Kayla Hui is a seasoned public health practitioner and health journalist. She has interviewed dozens of experts, reviewed numerous research studies, and tested a plethora of products to deliver well-researched product reviews and roundups. Her goal is to help readers make more informed decisions about their health and well-being.