Our top infrared thermometer was the ThermoWorks Hi-Temp Industrial IR With Circle Laser. It had supreme accuracy, adjustable emissivity, and a target-shaped laser that made aiming easy. It also had a large distance-to-spot ratio, which allowed for more specific readings from greater distances. We also liked the Wintact Infrared Thermometer. It was the most affordable model we tested and had fewer functions than our high-end favorites, but was still reliable.
We’re big fans of thermometers. They turn cooking from speculation into science—as long as you have the right one for the job. We love wireless versions for grilling and wouldn’t dream of roasting without a probe thermometer. We always have an instant-read pen in arm’s reach for quick temp checks. But our thermometer arsenal doesn’t stop there. When we want to sear, griddle, or make pizzas with precision, we turn to an infrared thermometer.
Infrared thermometers measure the temperature of surfaces. Unlike other types of thermometers, though, infrareds can be hard to easily validate in terms of accuracy, especially at home. With an instant-read thermometer, for example, you should be able to cut into a steak and see pink inside if the thermometer measures its internal temperature as 130°F. But unless you’re an Ooni expert, most home cooks won’t be able to tell if an 800°F surface temperature reading from their infrared thermometer is accurate, or a hundred degrees off. So how do you know which thermometer you can trust? That’s where we come in.
To find our infrared thermometers, we tested 10 notable models priced from $13 to $169. Along the way, we learned about the specific vocabulary that accompanies infrared usage. (Like, what is emissivity, anyway?) We also discovered the limitations of using this style of thermometer in a real-world environment, plus some tips for success. After over 300 readings, we found three infrared thermometers that were easy to use and dependable.
The Winners, at a Glance
As the name describes, this model projected a bullseye-shaped laser that offered a more accurate view of the entire target area than the single red dot of its competitors. Its screen was easy to read at a glance, and it had fully adjustable emissivity for taking the temperature of a wide range of materials. It could also be paired with wired probes (available separately) and display both readings simultaneously.
The Industrial IR Gun was a pared-down, mid-priced version of the Hi-Temp thermometer. It still had many of the same features (including high and low-temperature alarms, modes for displaying maximum, minimum, and average readings, and adjustable emissivity), but had a single laser instead of a bullseye-shaped one.
We were shocked (albeit pleasantly so) by the accuracy of this model, especially considering it was under $15. In our controlled accuracy test, its readings averaged less than 1°F away from the calibrator’s temperature. It was also the only model that allowed the user to fine-tune the measurements by 5°C (9°F) in either direction for calibration, although we didn’t have to with its out-of-the-box precision.
Accuracy Test: We used a portable infrared calibrator to verify each thermometer’s readings in a controlled environment. We set the blackbody target to 122°F, 250°F, 375°F, 500°F, and 700°F (allowing the temperature to stabilize for 30 minutes after every change) and took an average of five readings from each model at every step. Throughout the test, we also evaluated how easy it was to aim the thermometers accurately, examined if the displays were clear and readable, and noted how visible the lasers were.
Usability Test: To emulate real-world usage, we took the temperature of a pizza stone in a 500°F oven. We took an average of five readings for each thermometer (in case of glaring inaccuracies). Still, we primarily used this test to assess the thermometers’ ease of use, including how comfortable they felt in our hand and how quick it was to pinpoint the lasers inside a hot oven.
What We Learned
Distance-to-Spot Ratios Were Important to Know
As a rule, an infrared thermometer doesn’t just measure the small dot that their laser illuminates. In fact, the laser itself is only an approximate guide for the invisible measurement area, which actually changes in size depending on how close the thermometer is to its target. This correlation is known as the distance-to-spot ratio (sometimes called optical resolution) and varied in the models we tested. The most common ratio we saw was 12:1, which meant the target area would be about an inch in diameter when the thermometer was held 12 inches away.
Thermometers with larger distance-to-spot ratios could be held further back from their targets while still measuring a minute area. Our favorite ThermoWorks Hi-Temp Industrial IR With Circle Laser had a 30:1 ratio, so it could measure the same size spot as a 12:1 thermometer from over double the distance. This helped keep the thermometer cooler in the usability test (if the lens absorbed too much heat from the sweltering oven, it could have led to skewed readings). The Klein Tools IR1 Infrared Thermometer, on the other hand, had a 10:1 ratio. When held about three feet away from the hot pizza stone, it scanned a diameter of more than three-and-a-half inches. This wasn’t a deal breaker, but we were more cautious about pointing the laser in the center of the stone rather than getting close to the edges, which could have accidentally factored in the temperature of the oven floor.
Single-Dot Lasers Didn’t Show the Whole Measurement Target
Thermometers that had a single laser point (like the budget Wintact Infrared Thermometer) meant we only had a rough estimate of what area we were measuring, assuming the dot was at the center of that span (which didn’t seem to always be the case). That’s why we loved the outlined target that the ThermoWorks Hi-Temp IR offered with its circular laser beam since it did most of this visualization work for us.
All objects above −459.7°F (absolute zero) emit thermal energy—AKA infrared radiation—which is what infrared thermometers pick up. Emissivity is the efficiency at which thermal energy is radiated and is generally expressed on a scale from zero to one. Shiny surfaces tend to have lower emissivity because they reflect a higher quantity of energy than they emit, while dull and carbon-containing materials radiate more of their own heat.
A majority of the infrared models we tested had emissivity settings that could be fully adjusted from 0.1 to 1. Those that didn’t, including the Etekcity Infrared Thermometer and the Cuisinart Infrared Surface Thermometer, had a fixed value of 0.95 (which lines up with most organic substances, food, and water). We spoke to Kyle Halvorson, the Consumer Marketing Manager at ThermoWorks, to find out the importance of having variable emissivity. He explained that having a thermometer set to the wrong value could sometimes result in readings off by a hundred degrees or more. As an example, he told a story of measuring a stainless steel grill lid on a warm spring day and seeing it temp at -56°F when other parts of the grill were temping in the mid-80s. To get more accurate readings, he would have had to set the thermometer to stainless steel’s emissivity rating around 0.59.
“It’s not all that extreme,” Halvorson says. He clarified that, often, temperatures would vary by 10 or 15 degrees rather than a hundred or more, which would still be within a workable range when, say, measuring a cast iron skillet for searing temperatures or working with a pizza oven. It could also be difficult to find exact emissivity values of various materials to start with (we couldn’t find one for the cordierite pizza stone we used in the usability test, for example). Plus, emissivity can vary even among cookware of the same material, depending on wear and carbon buildup. Even so, we ultimately found it helpful when models (like the ThermoWorks Industrial IR Gun) had adjustable emissivities to correct dramatic inaccuracies.
Infrared’s Accuracy Was Relative
During our accuracy test, we measured the temperature of a precise calibrator target with a known emissivity of 0.95. We shot straight on and from a close distance. It told us how exact the thermometers were under near-perfect conditions, which weren’t really possible to accomplish in the real world. All infrared thermometers (including every one of the models we tested) are fallible to ambient temperature changes, particles in the air, lasers that are skewed from the center of the measurement area, and the aforementioned measurement distances and emissivity discrepancies. In some cases, a surface probe could be used to verify an infrared reading, but those are often costly and tend to have relatively low-temperature thresholds. For those reasons, we found it best to consider infrared thermometers’ readings as relative rather than exact during everyday use. Thermometers that had modes for maximum, minimum, and average temperatures across each trigger session also helped us better understand the general measurements across a surface. Although they come with a built-in level of variability, we still think infrared thermometers can offer vital insights for being a more informed cook.