Modern digital thermometers are quick, safe and accurate
Today's digital thermometers are fast, easy to use and safer
than traditional mercury thermometers. That said, most of them are made of
cheap, mass-produced plastic and have a poor reputation for durability, so consider
keeping an inexpensive spare on hand or planning to replace your thermometer
frequently; the average lifespan seems to be about a year.
We also found quite a few complaints about inaccurate
readings. While some of those are no doubt due to poor construction, it's clear
that many users aren't aware that a normal body temperature, taken orally,
isn't strictly 98.6 degrees. It can vary between 97 and 99 degrees, and different temperature sites on the same person will yield slightly different readings.
Types of Digital Thermometers
Oral thermometers are easy to use, familiar to most people, and accurate as long as you can hold still with the thermometer under your tongue until it generates an accurate reading -- sometimes 30 seconds or more. Most oral thermometers can also be used for taking axillary/underarm readings and rectal readings. Eating and drinking can alter the results of an oral temperature, so wait at least 15 minutes after meals or drinks to take your temperature.
Ear (Tympanic) Thermometers
Ear thermometers use an infrared ray to measure the temperature inside your ear canal. They're a great choice for children six months or older, who haven't mastered holding an oral thermometer under their tongue or won't sit still for long. Also, your ear temperature won't be affected by variables such as eating, drinking, or mouth breathing, although lying with your ear on a pillow, having lots of ear wax, or using a hearing aid can all affect the readings.
Although many parents are uncomfortable with the idea of using a rectal thermometer, they are still the gold standard in temperature measurement for infants and small children under three years of age. Although some stick thermometers can be used for rectal measurements, purpose-built rectal thermometers have a short, flexible probe for comfort and a bulb-shaped handle that keeps you from accidentally inserting the probe too far.
Temporal (Forehead) Thermometers
When used correctly, temporal artery or forehead thermometers can be just as accurate as oral and rectal thermometers -- and they're far less invasive. They use an infrared ray to measure the temperature of an artery in your forehead and offer very quick readings, usually in 10 seconds or less. The downside is that most temporal thermometers come with a little bit of a learning curve, and if you don't get the ray targeted correctly, you won't get accurate results.
Finding The Best Digital Thermometers
"The Best Baby Thermometer"
"The Best Thermometer for Kids and Adults"
We found several summaries of expert, hands-on testing at
Consumer Reports, Parenting, Wirecutter and The Night Light. These comparative
reviews are especially useful when it comes to eliminating user error and
determining which digital thermometers are most consistently accurate.
That said, user reviews from retail sites like Amazon,
Walmart and Target were just as important for learning how each digital
thermometer functioned in real-world conditions, which included squirmy babies,
fussy toddlers and sometimes recalcitrant adults too. Digital thermometers
aren't the only home health tools that must be accurate, reliable and easy to
use. We've also weighted heavily for real-world performance in our reports on blood glucose monitors and blood pressure monitors.
It's hard to
find fault with the simple, versatile design of an inexpensive digital
thermometer. A good, basic digital thermometer can give years of accurate,
reliable readings at very little cost.
With that in
mind, our best-reviewed digital thermometer is the (Est. $15). Although some users miss having a backlight on this
thermometer, they love its quick, accurate readings (usually in 15 seconds or
less, compared to 60 seconds for some of the competition) and appreciate the
fully waterproof housing that lets you wash the entire thermometer if need be.
Guard thermometer takes a single LR41 battery and can be used for oral,
underarm and rectal readings, although it's best suited to oral readings.
Underarm readings can be affected by skin temperature and, although the
Generation Guard's soft, flexible tip and washability make it ideal for rectal
readings, it lacks the broad base that dedicated rectal thermometers have to
keep you from accidentally inserting them too far.
Guard thermometer is accurate to 0.2 Fahrenheit or 0.1 Celsius, and it's easy
to switch between Fahrenheit and Celsius by holding down the power button. Its
features are simple but useful: it'll beep quietly (some say too quietly) to
tell you when a reading is complete, then display the last reading taken when
you turn it on.
Generation Guard thermometer is subject to a "no questions asked"
30-day money back guarantee, and their customer service department has
developed an excellent reputation for proactively doing everything they can to ensure customer happiness.
That's especially important for a product that, like all inexpensive stick
thermometers, tends to draw a lot of user concerns about its accuracy and for
sometimes arriving with dead or "almost dead" batteries.
If all you want
is a basic thermometer for occasional use or as a backup to your usual thermometer,
consider the (Est. $20). Users
generally love this thermometer's features, which include a fully waterproof
casing, recall of the last temperature taken, and a large, backlit display that
changes color according to the temperature reading. The same features garnered
the Vicks V966 Comfort Flex a "best thermometer for kids and adults"
pick from Wirecutter.
Comfort Flex is also fast, returning results in about eight seconds. However,
it only received Fair ratings for its accuracy and repeatability in a test from
Consumer Reports, and it draws enough user concerns about dead batteries and
accuracy that we can't award it Best Reviewed status (although, to be fair, all
digital thermometers receive a lot of those types of complaints). It is,
however, a good bargain if you're looking for a simple thermometer for
occasional use, and you can replace the CR1225 battery yourself.
and functional digital thermometers are more accurate and widely available than
ever, a few manufacturers are heading in the opposite direction, creating
digital thermometers that sync with your smartphone to enable advanced
The best of
these, the (Est. $15) thermometer, is priced to be competitive
with higher-end basic thermometers. It plugs into your mobile device's earphone
jack -- with or without an optional extension cord -- and harnesses your
smartphone's power to do most of the processing.
The result is a
light, durable device that can be used orally, under the arm or rectally, and
returns results in about 10 seconds. Users are very happy with the Kinsa Smart
Stick thermometer's accuracy, but it's the companion app that they really love.
The free app lets you track symptoms, chart temperature readings over time, and
note medications taken. You can even add photos to track conditions like a rash
or sore throat. The biggest hit of all, though, is the "bubble game"
that helps keep small children entertained and quiet as you take their
temperature. They can count or pop the bubbles that appear on the screen.
The Kinsa app
also lets you store tracking information for multiple people, or submit your
data anonymously to help crowdsource information about illnesses circulating in
your area. All of the above are roundly praised by user reviewers, and Kinsa's
proactive, helpful customer service department gets lots of kudos too. The only
major complaint we see is that users sometimes struggle to get the thermometer
synced to their phone, although we also note the usual complaints we see about
all digital thermometers, mostly durability issues and questions as to
however, two catches to be aware of. One, the Kinsa Smart Stick has no display
of its own, so you can only use it in conjunction with a smartphone that has
the matching app. Two, along with the user concerns about accuracy that seem to
accompany all digital stick thermometers, many note that this thermometer isn't
compatible with every device, so check the manufacturer's compatibility list before you buy. In particular, if you own an iPhone 7 or later -- the models
without a headphone jack -- you must use Apple's headphone-to-Lightning adapter
to connect the Kinsa thermometer to your phone.