Resolution is the first number most buyers look at on a thermal camera, and the easiest to misread. Here is what it means and how much you need.
Sensor resolution vs screen resolution
Thermal resolution is the number of pixels on the infrared sensor itself, such as 256×192. It is not the resolution of the screen or of any visible-light camera. A phone showing a crisp image does not mean the thermal sensor behind it has many pixels.
What the numbers add up to
- 96×96: 9,216 pixels
- 120×90: 10,800 pixels
- 256×192: 49,152 pixels
- 320×240: 76,800 pixels
- 384×288: 110,592 pixels
- 640×480: 307,200 pixels
Going from 120×90 to 256×192 is more than four times the pixel count, which is why that step is so noticeable in real use.
Why pixels matter: spot size
Each pixel covers a small patch of whatever you point at. The size of that patch grows with distance. As an example, a camera whose pixels each cover 2 milliradians sees about 2 mm per pixel at 1 metre, or roughly a quarter of an inch at 10 feet. For an accurate temperature reading, the target should span several pixels, so higher resolution lets you measure smaller things from further away.
How much do you need?
- Casual home checks: 120×90 can find big problems like missing insulation or a hot outlet.
- Serious home and trade work: 256×192 is the practical sweet spot for detail and price.
- Professional documentation or small, distant targets: 320×240 and above.
Watch for enhanced resolution
Some listings quote an upscaled or interpolated figure that is higher than the sensor's native resolution. Software enhancement can make an image look smoother, but it does not add real detail. When comparing cameras, always find the native sensor resolution.
Compare options by type in our buyer's guide, or browse handheld cameras and phone cameras.