Question 1

What is my screen resolution?

Accepted Answer

The "Physical resolution" row above is the number your device actually renders at — it is the CSS resolution multiplied by the device pixel ratio. On most phones the CSS resolution is much smaller than the advertised spec because the browser scales everything up.

Question 2

Why does my phone report a smaller resolution than advertised?

Accepted Answer

Browsers report resolution in CSS pixels, not hardware pixels. A phone advertised as 1170 x 2532 typically reports 390 x 844 CSS pixels with a device pixel ratio of 3. Multiply the two and you get the hardware number.

Question 3

How is the refresh rate measured?

Accepted Answer

The page counts how long the browser takes between animation frames over 150 frames and takes the median interval. That median is converted to a frequency. It measures the rate the browser is actually painting at, which can be lower than the panel maximum if the device is throttling or on battery saver.

Question 4

Why does my 120 Hz phone show 60 Hz?

Accepted Answer

Many phones drop to 60 Hz when the screen is mostly static, when battery saver is on, or when the browser is not on the high-refresh path. Scroll the page while measuring, turn battery saver off, and measure again.

Question 5

What is device pixel ratio?

Accepted Answer

It is how many hardware pixels the device uses to draw one CSS pixel. A ratio of 1 is a classic non-retina display, 2 to 3 is typical for modern phones and retina laptops. Higher values mean a sharper screen, not a bigger one.

Screen Resolution & Refresh Rate

Frequently asked questions