Thermapen ONE Review

A black Thermapen ONE thermometer registering 65.2 degrees Fahrenheit on its display screen

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Thermoworks just announced the release of the Thermapen ONE, dubbed as the world’s only one-second cooking thermometer.

That’s a bold statement, and judging from the promotional videos, a correct one as well.

Introducing Thermapen ONE

The Thermapen ONE is the newest addition to Thermowork’s Thermapen lineup that includes the Thermapen MK4 and the Classic Super-Fast Thermapen.

The Classic Super-Fast Thermapen (on the top) and the Thermapen MK4.(on the bottom)

The Classic Super-Fast Thermapen (on the top) and the Thermapen MK4.(on the bottom)

Both of the prior versions of the Thermapen featured response times of 2-3 seconds, which is still incredibly fast.

Not only does the Thermapen ONE feature a one-second response time, but it is also even more accurate as well.

Thermapen ONE black food thermometer in its package

It has an improved accuracy rating of ± 0.5°F (± 0.3°C), compared to a ±0.7°F (±0.4°C) accuracy rating for the MK4 and Super-Fast Thermapen models.

What else does the newest Thermapen feature?

Along with improved speed and accuracy, here are the other new features of the Thermapen ONE:

  • An upgraded, intelligent backlight.
  • A new, easier-to-access battery compartment is located on the back.
  • A 5-year warranty, compared to a 2-year warranty on prior models.

In this review of the Thermapen ONE thermometer, I will discuss its features, usability, durability, accuracy, and price to see if it’s worth your hard-earned money.


A black Thermapen ONE thermometer registering 64.4 degrees Fahrenheit while upside down on a white countertop

Thermoworks Thermapen ONE

If you’re unfamiliar with the world of thermometers then let me introduce you to the preeminent manufacturer of thermometers in the world today, Thermoworks.

Thermoworks produces a wide range of temperature measurement products from meat thermometers all the way to temperature data loggers.

Based in Utah and with partners around the globe, most notably Electronic Temperature Instruments, LTD in the United Kingdom, Thermoworks has years of expertise and experience when it comes to precise temperature monitoring.

The Thermapen series of professional-grade instant-read thermometers are world-renowned for their speed, accuracy, and durability.

The Classic Super-Fast Thermapen (actually the third version of the Thermapen) made its debut on June 1st, 2009, raising the bar of excellence for all meat thermometers virtually overnight.

The next Thermapen release, the Thermapen MK4, debuted in September of 2015, featuring enhancements such as an auto-rotating 360° display screen with an intelligent, light-sensor backlight.

(From the top), A Classic Blue Thermapen, a Pistachio-colored Thermapen MK4, and a Black Thermapen ONE meat thermometer displaying their backlit screen abilities

The Classic Thermapen at the top has no backlight, while the green Thermapen MK4 and black Thermapen ONE have backlights.

The MK4 also featured improvements in its sensor and probe assembly that made it slightly faster than the original Super-Fast Thermapen.

Now let’s look at the features and specifications of the Thermapen ONE.

Features and Specifications of the Thermapen ONE

Here are the important features and specifications of the Thermapen One.

The most important feature of the ONE thermometer is its one-second full temperature reading ability.

Not only that, it is even more accurate than the already accurate Thermapen MK4.

This means that you can expect an accurate reading of the food you’re cooking right after you insert the probe.

It is extremely important not to overlook the significance of this speed and accuracy.

I’ve tested a ton of meat thermometers here at Thermo Meat.

I can tell you that many thermometers’ temperature readings will jump around and not give you an accurate temperature, even after 5 seconds.

The fact that a thermometer is spending that extra time to figure out the temperature doesn’t instill much confidence in its overall accuracy.

The other upgraded feature is the intelligent backlight. What does this mean?

The intelligent backlit display screen of the Thermapen ONE

The intelligent backlit display screen of the Thermapen ONE.

Well, it is more receptive to touch than the Thermapen MK4. The backlight will turn on with the slightest nudge in low-light situations.

If there is one feature on the Thermapen MK4 that could use some tweaking, it’s the brightness of the backlight.

Is the Thermapen ONE backlight brighter? Unfortunately, no.


  • -58 t0 572 degrees Fahrenheit (-49.9 to 300 degrees Celsius) temperature monitoring range.
  • Accurate to within +- 0.5 degrees Fahrenheit from -58 to 392 degrees Fahrenheit.
  • One second response time.
  • 4.3 inch Probe.
  • High-Performance Type-K Thermocouple Probe.
  • 2,000-hour battery life. Takes one, 1.5 volt AAA battery.
  • Adjustable Sleep Mode from 10 to 180 seconds.
  • Waterproof rating IP67.
  • Rotating, Backlit Display  1 inch high by 1.54 inches wide.
  • Comes with a NIST-traceable calibration certificate.
  • Dimensions of 6.1 inches long, 1.7 inches tall, 0.74 inches thick.


The Thermapen ONE is everything you would expect of a Thermapen in terms of its usability.

It’s a simple as unfolding the probe, inserting it into food, and instantly getting a stable temperature read-out.

It may not seem like a lot, but there are many meat thermometers on the market that take 5 to 10 seconds before you get a stable temperature reading.

This is different than their reported response times, which is typically the first temperature given, then another 5 to 7 seconds of fluctuation.

This is not the case with the ONE. You insert it and you get a temperature that is accurate in one second.

Another usability feature that is nice is the improved backlight sensitivity.

The responsiveness of the MK4 did just an okay job of picking up lighting situations that weren’t bright but weren’t dark either.

The Thermapen ONE’s backlight responds to your touch and will turn on automatically whereas sometimes you had to move the MK4 model away from light to get the backlight to turn on.

The updated battery compartment of the Black Thermapen ONE allows easier access to user settings

The updated battery compartment of the Black Thermapen ONE allows easier access to user settings.


How does the Thermapen ONE compare to the other top meat thermometers on the market in terms of accuracy?

From left to right: ThermoPro TP-19, Thermapen MK4, Inkbird IHT-1S, Classic Super-Fast Thermapen, Lavatools Javelin PRO Duo meat thermometers all reading 135 degrees Fahrenheit

From left to right: ThermoPro TP-19, Thermapen MK4, Inkbird IHT-1S, Classic Super-Fast Thermapen, Lavatools Javelin PRO Duo meat thermometers all reading around 135 degrees Fahrenheit.

I tested the ONE’s accuracy to the other top meat thermometers and it performed as expected, coming out on top in terms of speed and accuracy.

(left to right) The Lavatools Javelin PRO Duo, Classic Thermapen, Thermapen ONE, Thermapen MK4, and the Inkbird IHT-1S instant-read meat thermometers all monitoring the same water bath temperature.

(left to right) The Lavatools Javelin PRO Duo, Classic Thermapen, Thermapen ONE, Thermapen MK4, and the Inkbird IHT-1S instant-read meat thermometers all monitoring the same water bath temperature.

Mind you, the differences in speed and accuracy aren’t too far apart and I would be happy to use any of these thermometers.

I liken it to a team of all-stars, with the Thermapen ONE easily being the best player in the arena.


The Thermapen ONE features the same IP67 waterproof rating as the Thermapen MK4.

An IP rating is an internationally recognized standard for rating a device’s ability to protect its components from water or dust.

A device that can withstand being submerged in water up to a meter for 30 minutes with no detrimental effects has an IP rating of 67.

Along with its waterproof ability, the Thermapen ONE’s body is shockproof and also features antimicrobial silver ion technology to inhibit bacterial growth.


The current price for the Thermapen ONE is $105.

There’s the old adage that price is what you pay, value is what you get.

What are you buying when you buy a Thermapen?

You’re buying confidence and peace of mind that you’re serving food at the temperature you want to serve it at.

Yes, there are many lower-priced meat thermometers you can purchase, but none are as fast, accurate, or as well made as a Thermapen.

The price you pay for something is determined over time, not just the money you fork over at the cash register.

I judge all of the meat thermometers I test against my Thermapens, they are the best.

I’ve had my Classic Super-Fast Thermapen for almost nine years now, and only recently did I need to change the battery.

How many devices do you have in your life that have that type of high-level performance and dependability?

Here’s a secret (not really a secret, but some people might not know this) I’ve learned over time, you actually save money when you pay more for quality things.

A Thermapen is a quality product, one that will continue to give me the highest value for years to come.

Pistachio-colored Thermapen MK4 at the top and black Thermapen MK4 on the bottom

Thermapen ONE vs Thermapen MK4

What are the differences between the Thermapen ONE and the Thermapen MK4?

The most notable difference is that the Thermapen ONE features a one-second temperature reading response time compared to the 2-3 second response time of the MK4.

The other important difference is the Thermapen ONE has a brighter backlight that is more sensitive to changes in ambient lighting conditions.

Another design change is the decision to move the battery compartment from the end of the thermometer to the back of the body for easier access to the user settings panel.

The body of the Thermapen ONE is also a little bit smaller than the Thermapen MK4.

Here are the dimensions for both:

  • Thermapen ONE-6.1 W x 1.7 H x 0.74 D inches (156 W x 48 H x 19 D mm)
  • Thermapen MK4- 6.2 W x 1.97Hx 0.75 D inches (157 W x 50H x 19 D mm)

Final Verdict

When Thermoworks announced the release of the Thermapen ONE the main question in my mind was, what’s new?

The key features that will set the Thermapen ONE apart are the improved speed and accuracy as well as the improved backlight.

Considering that the Thermapen MK4 was already the fastest and most accurate meat thermometer out there, that’s quite an accomplishment.

The Thermapen ONE is indeed a touch faster, but I find the more-sensitive backlight to be just as nice a feature as the improved speed and accuracy.

The MK4 model has trouble sometimes with lighting situations that can best be described as not bright, but not dark either.

It’s this in-between lighting situation where the Thermapen ONE’s backlight shines (had to do it), turning on even with the slightest touch.

Could the backlight be brighter? Yes it could.

But when you couple it with its best-in-class speed, accuracy, waterproofing, and reliability, you’ve got yourself the best meat thermometer you can buy.

It’s not cheap, but you’ll have piece of mind for years to come.