The 4 Best Smartphone Thermal Cameras of 2021

A smartphone thermal camera is the best option if you need to use thermal imaging but you don’t want to spend much on a device. These devices that attach to your phone are less expensive, have a high resolution and are very easy to use

We researched and compiled a list of 4 great thermal cameras that attach to your smartphone which are worth considering.
The 4 Best Smartphone Thermal Cameras of 2021
ProductTypeResolutionBattery capacityWaterproofLCD screenPrice

FLIR ONE Pro

FLIR ONE Pro
Smartphone (2 different versions – Android & iOS)160 x 12045 minutesNoUses Smartphone screenClick for more info

Hti HT-301

Hti HT-301
Smartphone384 x 288Uses Phone BatteryNoUses Smartphone screenClick for more info

Seek Thermal Compact PRO

Seek Thermal Compact PRO
Smartphone320 x 240NoYesNoClick for more info

Seek Thermal Compact

Seek Thermal Compact
Smartphone206 x 156NoYes Click for more info


Let’s have a look at each product in particular.

FLIR ONE Pro

ProductTypeResolutionBattery capacityWaterproofLCD screenPrice

FLIR ONE Pro

FLIR ONE Pro
Smartphone (2 different versions – Android & iOS)160 x 12045 minutesNoUses Smartphone screenClick for more info
The first smartphone thermal camera we want to look at is the Flir One Pro. This is one of the most popular devices in its class and there are good reasons for that. It is equipped with 3 things: An infrared sensor with a 160 x 120 resolution, a 1440 x 1080 visual camera for MSX image enhancement and a small battery that should last for 45-60 minutes.

The way you use it is you attach it into your smartphone via its Android USB-C, micro USB or Lightning connector for iPhone depending on which platform you use since it is available for both Android and iOS devices. The device comes in all three versions but you will have to decide on the connector beforehand and you can’t change it afterwards. You can however use an adaptor from eBay or Amazon, but do consult the list of compatible adapters beforehand as not all of them work. Then you download the smartphone app from either the Play Store or App store and you’re ready to start capturing thermal images.

Its embedded thermal imaging system can measure temperatures between -4 -> 752°F( -20 to 400 C) with a thermal sensitivity of 0.07° C. The app is great, it has multiple color palettes, different image modes (MSX, Visual, Thermal-Only) and lets you adjust the emissivity and ambient temperature together with the temperature units (Fahrenheit and Celsius). The images are captured in JPG format and you can also record MP4 Video and Time lapse.

Like most Flir cameras, it comes with a 2-10 warranty, 2 for the entire infrared thermal imaging system and 10 just for the thermal sensor.

There are two other versions of this thermal camera for smartphones which differ slightly. The Flir One Gen 3 has an 80 x 60 resolutions and less app features but costs half the price and the Flir One Pro LT has the 80 x 60 pixel resolution, but the app features of the Pro and costs right in between the Pro and the standard Gen 3.

Hti HT-301

ProductTypeResolutionBattery capacityWaterproofLCD screenPrice

Hti HT-301

Hti HT-301
Smartphone384 x 288Uses Phone BatteryNoUses Smartphone screenClick for more info
The Hti HT-301 is the smartphone thermal camera with the highest resolution out of all the ones listed here. It is only available for Android devices and it comes with a USB-C connector along with a micro USB adapter. This device will turn your smartphone into a high resolution thermal camera with a sensor that outputs a 384 x 288 thermal image, totaling 110,592 pixels.

Plus, because it is built in mainland China and not in the US, it doesn’t have to abide by EAR export regulations and it can achieve a 25Hz refresh rate, much higher than the 9Hz to which Flir cameras are limited to. We encourage you to check out the night vision video samples on Youtube and see for yourself, the results are impressive.

This phone attachment doesn’t have a visible light camera, just the infrared sensor but it costs more than both the Seek Compact and the Flir One just because of the more powerful thermal sensor. The standard smartphone app is buggy and thus we used it with the Thermviewer app which offers more functionality and color palettes without the software bugs.

Here is our complete review of the Hti HT-301

Seek Thermal Compact PRO

ProductTypeResolutionBattery capacityWaterproofLCD screenPrice

Seek Thermal Compact PRO

Seek Thermal Compact PRO
Smartphone320 x 240NoYesNoClick for more info
The biggest advantages of the Seek Thermal cameras is that their smartphone thermal camera modules have a higher resolution and longer detection distance. This one is no exception because its thermal image sensor outputs a 320 x 240 resolution and can detect heat signatures up to 1800 feet away putting it at a level above the Flir One’s thermal camera from this point of view.

But it doesn’t have the MSX technology which weighs a lot in the overall quality. However, the thermal resolution is so high you most likely won’t even need image overlaying. It measures temperatures from -40F° to 626°F (-40°C to 330°C) with a 0.07 sensitivity. It is not waterproof nor dustproof just like most thermal imaging cameras for smartphones.

This one is also available for iPhone and Android smartphones as a phone attachment. You can find the Seek Thermal app on both app stores and we have to say that the user interface has improved a lot, it looks much more polished and offers the adjustments that you would expect from a pro-grade thermal camera like adjusting the temperature scale, geo-tagging, emissivity and reflected temperature.

Seek Thermal Compact

ProductTypeResolutionBattery capacityWaterproofLCD screenPrice

Seek Thermal Compact

Seek Thermal Compact
Smartphone206 x 156NoYes Click for more info
The standard Seek Compact is just a low-spec version of the Seek CompactPro smartphone thermal camera, but it is mentioned here because it provides the best value out of all these smartphone thermal imagers.

Given that it has the same price as the Flir One and it delivers an image resolution of 206 x 156 with a detection distance of up to 1000 feet, we can declare this as the thermal camera for smartphones which offers the best value.

In terms of its temperature measurement abilities, it can measure anything in a thermal scope from -40 -> 626 °F (-40 to 330° C). This is a great camera to use for home inspections because it is cheap and the sensor is good enough to allow you to do simple electrical inspections for fuses that might overheat, check for plumbing leaks or do your own HVAC evaluation.

Which is the best smartphone thermal camera?

In terms of image resolution, the Hti-301 has the highest thermal resolution. In terms of value for money, nothing beats the standard Seek Thermal Compact, but our overall favorite when all things are considered is the Flir One Pro. The CAT S61 and S62 have the advantage of having the thermal sensor embedded inside them which does give the feeling of a polished and complete product.

Can I use my phone as a thermal camera?

Yes, but only if you have one of these thermal cameras attached to it. Standard phones are not equipped with any kind of thermal sensors, with the exception of the CAT S61 and CAT S62 Flir and a few other models which you will find below. So you need to know that any apps which you may find on the Play Store or App Store claiming to be able to offer infrared vision are most likely not going to deliver on that promise, unless you have a physical infrared sensor attached to the phone or integrated in it.

Ok then, so how do you turn your phone into a thermal camera?

First, you will need to buy one of the smartphone thermal imagers listed here, either a Flir One Pro, Seek Compact, HT-301 or PerfectPrime IR202, which will cost between 150$ and 700$ depending on the model you choose then download the specific app for them and you are good to go. Now your smartphone has full thermal vision.

Which phone has a thermal camera bult-in?


Here is a list of phones which already have a thermal camera built into them:

  • CAT S61 Flir – Made by Caterpillar, uses a Flir Lepton 3 sensor with a 160 x 120 infrared resolution, spectral range from 8 to 14, pixel size of 12 and a 0.05°C sensitivity.

  • CAT S62 Pro – This model uses a Lepton 3.5 thermal sensor with a thermal resolution of 160 x 120 (19,200 thermal pixels), a temperature range between -4°F to 752°F (-20 °C to +400 °C), a thermal sensitivity of 0.05°C together with a +/-5°C accuracy. The sensor is integrated inside an enclosure that is completely waterproof.

  • Blackview BV9900 Pro – Uses the Flir Lepton 2.5 sensor with an 80 x 60 IR resolution.

  • Blackview BV9800 Pro – Uses the same type of 80 x 60 sensor. Most likely a Lepton 1.5 or 1.6 sensor.

  • Ulefone Armor 9 Pro – Uses the same Lepton 2.5 as the BV9900 Pro.



Manufacturers of smartphones with integrated thermal cameras have been reluctant to disclose the exact models of image sensors that they are using but if you do some research you can find the exact model, usually based on the specs.
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