is supported by our Pitmaster Club. Also, when you buy with links on our site we may earn a finder’s fee. Click to see how we test and review products.

ThermoPro TP-420 IR and Instant Read Thermometer Review

Share on:
ThermoPro TP-420 IR and Instant Read Review

The ThermoPro TP-420 is a combination infrared (IR) gun and an instant-read thermometer at an attractive price point. The infrared sensor gives the user the temperature of a cooking surface and the probes measure the internal food temperature.


The sensor has a 12:1 measurement cone, meaning that at 12″ from a surface the sensor will detect the temperature in a 1″ diameter circle. This allows the user to point the sensor at a small area, giving better control of the measurement. There is no laser pointer, so one has to be careful to orient it toward the surface of interest. Pressing the Scan button activates the IR sensor, and it takes measurements for the duration of the button push. When the button is released, the measurement is held. Pressing the Mode button toggles through the held value, the minimum value, and the maximum value observed during the Scan. Oddly, the display is upside down when the sensor is pointed downward, and the display does not rotate as the thermometer’s orientation is changed. Using two expensive ThermoWorks IR thermometers as references, the ThermoPro unit read about 20°F higher at 400°F than the reference thermometers. This is probably an acceptable deviation.

An infrared thermometer’s reading is dependent on a parameter called emissivity. It relates to how much energy is radiated from the surface at a given temperature. A dark surface emits more energy than a shiny surface. For maximum accuracy, the value set in the thermometer should match the emissivity of the surface being measured. This thermometer allows the user to adjust the parameter if desired. It comes set at 0.95 by default, a value used by most thermometer manufacturers. Most users will never change the factory’s setting.


The probe has its own temperature display. It shows the instantaneous temperature value; there is no hold/min/max function. Again, the display does not rotate, so the reading must be taken from the measurement position. this is slightly awkward, but not a deal breaker. The probe’s accuracy at food temperatures was very good, and the response time was also good.

The build quality of this thermometer leaves something to be desired. There are many nooks and crannies where food residue could accumulate which can be a possible hygiene problem. The battery cover does not include any seals to prevent water entry, so the user must be careful around a faucet. Better thermometers, including the most recent ThermoPro offerings, are constructed with seals to impede water ingress. Perhaps this failing is OK at this price point, but it is a risk. You could spend several times the price of this thermometer to get better moisture immunity if you’re so inclined.

As my wife likes to remind me, you don’t get what you don’t pay for. This is true with this thermometer. Design and construction reflect the price point. This is the least expensive IR/instant read thermometer I’ve tested. It performs well but is vulnerable to moisture and food contamination. If you’re careful with your tools, this thermometer could be a good value. If not, this might not last long. Ultimately it is your call, your choice.


The warranty isn’t stated in the accompanying materials. Contact info for the manufacturer includes telephone numbers and an e-mail address. The user’s manual is well-written and comprehensive. Overall, this is a decent value that gets a Silver Medal for price/performance ratio.

Haven't found what you want?
Click the buttons below to search our complete database of reviews:

Product Information:

  • Thermometer Function:
    Hand Held/Instant Read, Infrared Gun
  • Item Price:
    $ 29.99
    *Price Subject To Change
  • Where to buy (buying from this supplier supports this website):
  • Probe:
    Length: 4.25" (108mm), diameter: 0.138" (3.5mm), tip: 0.081" (2mm)
  • Battery Type:
    2xAAA (supplied)
  • Battery Life:
    Not specified
  • Safe Operating Range:
    Not specified
  • Min & Max Temp:
    IR: -58 to 1022°F (-50 to 550°C); Probe: -58 to 572°F (-50 to 300°C)
  • Display Precision:
  • Actual Temp at 32 Degrees:
  • Actual Temp at 130 Degrees:
  • Actual Temp at 225 Degrees:
  • Actual Temp at 325 Degrees:
  • Speed from 32 to 212 Degrees:
  • Speed from 32 to 212 Degrees:
  • Numbers Display Size:
    IR: 0.40" (10mm); Probe: 0.36" (9mm)
  • Water Resistance Rating:
    Not water resistant
  • Weight:
    4.15 oz. (117g)
  • C/F Switch:
    Built in CF switch
  • Backlight:
    Built in Backlight
  • Auto shutoff:
    Has Auto Shutoff
  • Color Options:
  • Thermometer Sensor:
  • Additional Features:
    Min/Max/Hold button for IR sensor
  • Included:
    Thermometer, batteries, instructions
  • Alarms:

Published On: 8/4/2022 Last Modified: 8/11/2022

  • Bill McGrath, Chief Thermometer Reviewer - Bill McGrath is's Thermometer Maven. He has sophisticated equipment, an electrical engineering degree from Cornell University, and an MBA (almost) from UC Berkeley. Despite being mostly retired, he is still the person responsible for developing and updating all of ExxonMobil's training modules.


High quality websites are expensive to run. If you help us, we’ll pay you back bigtime with an ad-free experience and a lot of freebies!

Millions come to every month for high quality tested recipes, tips on technique, science, mythbusting, product reviews, and inspiration. But it is expensive to run a website with more than 2,000 pages and we don’t have a big corporate partner to subsidize us.

Our most important source of sustenance is people who join our Pitmaster Club. But please don’t think of it as a donation. Members get MANY great benefits. We block all third-party ads, we give members free ebooks, magazines, interviews, webinars, more recipes, a monthly sweepstakes with prizes worth up to $2,000, discounts on products, and best of all a community of like-minded cooks free of flame wars. Click below to see all the benefits, take a free 30 day trial, and help keep this site alive.

Post comments and questions below


1) Please try the search box at the top of every page before you ask for help.

2) Try to post your question to the appropriate page.

3) Tell us everything we need to know to help such as the type of cooker and thermometer. Dial thermometers are often off by as much as 50°F so if you are not using a good digital thermometer we probably can’t help you with time and temp questions. Please read this article about thermometers.

4) If you are a member of the Pitmaster Club, your comments login is probably different.

5) Posts with links in them may not appear immediately.



Click to comment or ask a question...


These are not paid ads, they are a curated selection of products we love.

All of the products below have been tested and are highly recommended. Click here to read more about our review process.

Use Our Links To Help Keep Us Alive

Many merchants pay us a small referral fee when you click our “buy now” links. This has zero impact on the price you pay but helps support the site.