What goes wrong in this category
System readings are the ones people need for a support ticket rather than for a diagnosis. What resolution is this display actually running at, what is the device pixel ratio, what refresh rate is the browser getting, how deep is the colour buffer. They are also the readings most often misread, which is why this page exists rather than just the numbers.
The most common confusion: a 4K laptop that reports 1920 by 1080. That is not an error. The operating system is scaling the display and the browser reports the CSS resolution, which is the physical resolution divided by the device pixel ratio. Multiply the two back together and the panel's real pixel count reappears. The same distinction explains why the viewport figure changes when you resize the window while the screen resolution does not.
The refresh rate is the one figure here that is genuinely an estimate, and it is labelled as one everywhere it appears. It is counted from animation frames, and browsers cap frame delivery on battery, in background tabs and under load. A reading of 59 on a 60 Hz panel is the measurement, not the monitor.
Which test for which symptom
| Symptom | Test | What it tells you |
|---|---|---|
| You need your screen resolution for a support ticket | Screen Info | Screen, available area and viewport size as the browser reports them, copyable as one block |
| Images look soft on a high-resolution display | Screen Info | The device pixel ratio, which explains why a 4K panel reports 1920 by 1080 in CSS pixels |
| You want to know your refresh rate | Screen Info | An estimate counted from animation frames, labelled as an estimate because browsers cap frames |
| A page looks wrong at a certain window size | Screen Info | The live viewport size, which changes as you resize while the screen resolution does not |
Compiled by MyGearCheck. The last column is deliberately bounded: these tests observe what reaches the browser, which is enough to separate hardware from software and not enough to name a failing component.
Guides for system
A test tells you what is happening. These explain what to do about it, including when the honest answer is that nothing is wrong.