UPDATE: The Thermoworks Thermapen Mk4 is no longer available. It has been replaced by Thermoworks’ newest instant read thermometer the Thermapen One.

Thermoworks Thermapen Mk4

Today we take a deep dive into the Thermapen Mk4. 

I can’t think of a tool that we use more both in the indoor and outdoor kitchen than an instant read thermometer. Food safety is so important and you need to be able to read temperatures of your food when you’re cooking. Having an easy to use device we can rely on to give us the fastest and most accurate results makes everything we cook better.

So, is the Mk4 the best instant read thermometer available?

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Thermoworks Thermapen Mk4 Features

  • Readings within 2-3 second with ±0.7°F accuracy
  • Temperature displays in °C or °F
  • Auto rotating display for best viewing angle
  • Waterproof to IP67 rating
  • Intelligent backlight
  • Available in 10 colors

Reading Temperature

Accuracy: Let’s start with how accurate this meat thermometer is. Let’s think about it, with any digital instant read, if it’s not accurate, it doesn’t matter how quickly we get to the temp, right? The Thermapen gives an accurate temperature within 0.7 degrees Fahrenheit or 0.4 degrees Celsius. That means we’re talking about accuracy within 1 degree for whatever temperature you’re measuring.  Calibration is built in in case it ever loses accuracy over years of use.

Sensor: When it comes to measuring temperature, it’s useful to note that the sensor is in the end cone portion of the probe, so when you’re measuring temp, you can get very precise with it. If you know that you’re just using the tip of the cone to get your reading, you can check a very precise location and know that you’re measuring exactly what you’re after. It takes the guesswork out of things.

Probe Length: Like any visiting alien ship crew will tell you, probe length is very important in getting the right kind of measurement. With a 4 inch long probe, the Mk4 can get to the center of just about any cut of meat we can imagine without any difficulty. The probe is also quite a bit more narrow than most of the wireless probe meat thermometers that we use in barbecue settings.

At about half the overall width, the Thermoworks probe isn’t going to leave a gaping hole in your meat where juices will find their way to the surface. We know so many people who use the Mk4 in steak cookoff contests because they can read temperatures precisely without leaving probe holes in their competition steak from meat thermometers.

Speed: Speed is another factor that we want to consider with any instant read thermometer. The manual and Thermoworks website say that the Thermapen will read within 2 to 3 seconds, and we find it to be sub 2 seconds in our testing. It is by far the fastest and most accurate digital instant read thermometer we’ve tested here at the Lab. The probe is continuously reading temperature, so you’re never locking in to a temp whenever you’re using the Mk4.

Since we’re cooking over hot grills most of the time, speed is a key factor for us. There’s no way that we can hold an instant read thermometer over a 700 degree grill for any period of time while checking the temperature of a steak that we’re searing. The ability to read at around 2 seconds is critical for us, or we’d have to pull everything off the grill to check internal temp, and nobody wants to mess up those perfect grill marks, right?

The Thermapen is always measuring temperature, so the first number you’ll most likely see when you open the probe is the temperature of the room you’re in. With such quick readings, you’ll see the air temp number before you even get it into the food you’re wanting to measure.

Programming: You can change the readout on the Thermapen between Fahrenheit & Celsius easily, so when your friends from the United Kingdom come over, you’re covered.  Decimals can also be turned on and off. 

Thermapen opened up for programming

Ease of Use

When it comes to turning the Thermapen on, you just open the probe and it turns on automatically. It has auto-on and auto-off built in, so there’s no hunting for power buttons out in the dark when you want to see how done your steak is. The thermometer automatically turns off whenever you close the probe against the body of the unit, or the motion-sensing feature kicks in whenever you set the thermometer down and it remains inactive for 30 seconds. To wake it up, just pick the unit up and it snaps back to life. The great thing is that the motion-sensing sleep and wake mode helps to save on battery life.

Unlike some of its competitors, the probe folds up against the body for storage to protect the probe and take up less space. Other meat thermometers might have a probe cover that will likely get lost or a pouch to store it in, but with the Thermapen it’s built to protect itself when not in use. We keep ours in the silverware drawer in the kitchen, so it’s getting thrown around and whacked against the side of the drawer each time the kids need a utensil. It’s stood up to the abuse and functions just like the days we picked it up 6 months ago.

Color Options for the Thermapen Mk4

Unlike many of the other instant read thermometers on the market, this one comes in 10 color options, so there’s one that will match your color scheme. We went with the blue because it ties in well with our logo and brand colors, but we’re just marketing nerds, so there’s probably other reasons to choose color, but that’s what drew us in.


There’s a 2 year warranty on the Thermapen Mk4, so I personally don’t worry about something happening to it. Mine’s been knocked off the counter and thrown into a drawer multiple times, and it’s no worse for wear.


The price of the Thermapen Mk4 at the time of this writing is $99. You can find plenty of cheap thermometers out there that will pretend to be as good as the Mk4 but none of them ever are. We find it to be well worth the money because we use it every time we fire up a grill or smoker and quite a bit in the indoor kitchen as well. I use it more than my spatula, tongs or any grill we have here at the Lab. It’s one of the top 3 tools we have in any cooking environment.

What We Loved About the Thermapen Mk4

Auto Rotating Display– One of my favorite features on the Mk4 is that the display automatically rotates. (This is a new feature that didn’t exist in the classic Thermapen). No matter which way you hold the thermometer, you’re able to read the temperature right side up. The auto rotating display is a feature that we love, but if it’s not your cup of tea, you can even set it to 2 way or single orientation as well to fit your preferences.

Intelligent Backlight– An excellent new feature that we didn’t see in the classic Thermapen is the backlight. The display will glow orange whenever the unit senses that it’s dark using the built in light sensor found on the handle. We don’t have to worry about finding a button or clicking through display screens to turn on the light, it’s automatic, and it’s easy. If I need light to read the display, it will be on. If I don’t, it’s turned off. It’s a great feature that I don’t even think about most of the time because I’ve just gotten so used to it always being exactly what I need.

Simplicity– One of the things that we see on quite a few competitors to the Mk4 are additional features not included on the Thermapen. The thing is, I find the exclusion of these features to be a reason to like the Thermapen even more. Having a setting to remember high temperature and low temperature is something we’ve never used before, and can’t see having a use for in the future. Same with other things that clutter up the thermometer. The Mk4’s simplicity is one of its biggest features in that it does exactly what you need it to, and nothing more.

Waterproof– The Thermapen is waterproof for 30 minutes in 3 feet of water; specifically it’s waterproof to IP67 rating. Don’t worry about dropping it into the SouxVide or sink when you’re washing it. I know we’ve left ours out on the grill overnight when it rained, and it’s still working like the day we got it. It’s a survivor. 

Easy to Hold– The Mk4 is comfortable in the hand. It’s not a small thermometer, and for us that’s a good thing. There’s plenty of room to hold on to the handle and still see the digital readout while feeling confident that we’re not going to drop it. Many competitors’ thermometers are so small that they don’t feel good in the hand, and we think this is a great size for a handheld unit.

Fits in tight spaces– The switchblade style of the thermapen allows us to sneak into tight spaces to get the internal temperature of meat without having to disrupt how we have things laid out. In kamado style cookers, we often use the upper rack which only allows for 5 inches of clearance between grates. That means that we don’t always have the room to stick a meat thermometer in when it’s all the way open. There’s enough rigidity in the probe as it’s swinging open that we can use it at any angle our cooking setup calls for.

Battery Life– Because of the motion-sensing sleep and wake feature, the battery life of the Mk4 is much longer than it’s predecessor, the classic Thermapen. This new edition can last up to 3,000 hours on a single AAA battery. That’s an impressive battery life. 

Opportunities for Improvement

Vertical Orientation Readout– The only thing that I’d like to see improved on this meat thermometer is the size of the readout on the auto rotating display when it’s being held in vertical orientation. It’s a bit smaller than what you get when you’re holding it horizontally, and I like the size of the horizontal more than the smaller size of the vertical. It was a stretch to find anything that I’d like to see improved, and that’s the only thing that I came across that I think could be improved.


The Thermapen Mk4 gets our highest rating for an instant read thermometer. In our opinion this is the best instant read meat thermometer available at this time. All the others just can’t compete with Thermoworks when it comes to speed and accuracy.