How to check your screen resolution and refresh rate
As soon as the page opens you see your physical resolution and refresh rate. The refresh rate is measured by timing screen redraws for about 2 seconds, so keep this tab in front while it measures. Below are the CSS resolution, viewport size, scaling, aspect ratio, color depth, HDR, color gamut, OS and browser.
Press Copy all info to copy everything as text — handy for support tickets, bug reports or checking a used monitor.
- Using two monitors? Drag the browser window to the other display. If its scaling differs, the values update automatically and the refresh rate is re-measured; otherwise press Measure Hz again.
- Resize the window and the viewport value updates live, which helps when building responsive layouts.
- Enter your screen size in inches to get PPI and pixel pitch.
Physical resolution vs CSS resolution vs scaling
Physical resolution is the number of pixels the display actually draws. CSS resolution is the logical size web pages see. The ratio between them is the device pixel ratio, shown here as scaling. A 1920×1080 laptop at 125% scaling looks like 1536×864 to web pages; a 2560×1440 monitor at 150% looks like about 1707×960; a phone with a ratio of 3 draws a 390×844 CSS screen with 1170×2532 pixels.
This tool multiplies the CSS screen size by the pixel ratio. If you lower the display resolution in Windows, you see the lowered value. On macOS with a scaled resolution, you see the resolution macOS renders at — for example, a screen that “looks like” 1470×956 reports 2940×1912 — which can differ from the panel’s native resolution.
In Chrome, Edge and Firefox, browser zoom also changes the pixel ratio; Safari’s page zoom does not. If the ratio is something an OS can’t set (such as 110% or 90%), the tool warns you — press Ctrl+0 (⌘+0) and check again.
How the refresh rate is measured, and why you may see 60 Hz
There is no web API that reports the display refresh rate directly. As the Chrome team notes, the best a page can do is compare the timestamps of successive requestAnimationFrame callbacks, which generally match the display’s refresh rate. This tool collects about 2 seconds of frame intervals, uses the median, and snaps to a common rate (60, 120, 144, 165, 240 Hz…) when within 3%. It also shows frame-time jitter and the share of late frames.
- Display set to 60 Hz: many high-refresh monitors start at 60 Hz in Windows. See the steps below.
- Battery saving: depending on its setting, Chrome’s Energy Saver turns on when the device is unplugged or the battery is low, and it reduces the display refresh rate. Plug in and measure again.
- Safari on iPhone/iPad: may limit web page animation to about 60 fps by default, so ProMotion devices can read 60 Hz; Low Power Mode can lower it further.
- Background tabs: most browsers pause animation frames in hidden tabs, so measurement only runs while the tab is visible.
- Variable or dynamic refresh rate: displays that drop their rate when little is moving can give varying results. Measure a few times and look at the highest.
Set 144 Hz or 165 Hz in Windows, and the refresh rate on a Mac
In Windows 11 open Start > Settings > System > Display > Advanced display and pick a value next to Choose a refresh rate. Microsoft notes that rates marked with an asterisk (*) don’t support your current resolution, and that dynamic refresh rate requires a display with VRR and at least 120 Hz. If the rate you want is missing, check that the cable and port (DisplayPort or the HDMI version) support it.
On a Mac choose Apple menu > System Settings > Displays and use the Refresh Rate pop-up menu. The ProMotion display on 14- and 16-inch MacBook Pro models with Apple silicon adapts up to 120 Hz. After changing settings, press Measure Hz again to confirm.
Laptop scaling, color gamut, HDR and color depth
Windows scaling lives under Settings > System > Display > Scale & layout; Microsoft recommends the option marked (Recommended) in most cases. Scaling changes how large things are drawn, not the physical resolution, so it does not reduce sharpness.
Color gamut reports the widest range the browser thinks your screen covers: sRGB, then Display P3, then Rec.2020. HDR reflects whether the browser sees a high-brightness, high-contrast output with more than 24-bit color — an HDR monitor shows SDR when Windows HDR is off. Color depth is what the browser reports; some browsers always return 24 for compatibility, so check the manufacturer’s spec for 10-bit panels.
FAQ
My monitor is 144 Hz but this shows 60 Hz.
Usually Windows is set to 60 Hz. Change it under Settings > System > Display > Advanced display. If 144 Hz is not listed, check the cable and port. On a laptop, plug in the charger and measure again.
The physical resolution doesn’t match my monitor’s spec.
The OS resolution may be set lower than native, browser zoom may be active, or macOS may be using a scaled resolution. Press Ctrl+0 and make sure the display resolution is set to the recommended value.
Does 125% or 150% scaling reduce image quality?
No. Scaling only decides how large text and icons are drawn; the physical resolution is unchanged. Some old apps that don’t support scaling can look blurry, though.
My phone is 120 Hz but it shows 60 Hz.
Safari on iOS may limit web page animation to about 60 fps by default, and Android power-saving or refresh-rate settings can lower it too. Treat the result as the rate the browser allows web pages.
How do I check a second monitor?
Move the browser window to that monitor and press Measure Hz again. Resolution and scaling update automatically when the scaling differs. Chrome and Edge also show whether an extended display is in use.
Is any of this sent to a server?
No. Everything is calculated and shown in your browser, and only copied to your clipboard when you press Copy.