Free Online Device Test
Free Screen Resolution Test
Check your screen resolution, browser viewport, estimated physical pixels, device pixel ratio, colour depth, orientation and refresh rate.
Works on compatible computers, tablets and mobile devices. No device permission is required.
Check Your Screen
Measurements update automatically when the window size or device orientation changes.
Browser-reported display
The live tool shows the screen dimensions reported by the browser, the estimated physical resolution and the current screen orientation.
Primary screen measurements
- Screen size
- The complete screen width and height reported in CSS pixels.
- Estimated physical resolution
- A practical estimate calculated from browser-reported screen size and device pixel ratio.
- Browser viewport
- The visible webpage area inside the current browser window.
- Device pixel ratio
- The relationship between physical display pixels and CSS pixels at the current scaling configuration.
Screen and Browser Information
- Available screen area
- Excludes operating-system interface areas.
- Viewport excluding scrollbar
- Document space available for page content.
- Orientation
- The current portrait or landscape orientation.
- Colour depth
- Bits available for representing colour.
- Estimated refresh rate
- An approximate animation-frame refresh-rate reading.
- Fullscreen status
- Shows whether the test panel is fullscreen.
- Screen aspect ratio
- The proportional relationship between screen width and height.
- Viewport aspect ratio
- The proportional relationship between browser content width and height.
How Your Display Is Classified
The live test classifies the estimated physical resolution using common display categories such as HD, Full HD, QHD, 4K and 5K or higher.
Current Browser Breakpoint
The active responsive-layout breakpoint is based on the current browser viewport width.
- Mobile — up to 599px
- Tablet — 600px to 899px
- Laptop — 900px to 1279px
- Desktop — 1280px and above
No Device Permission Is Required
This test reads standard browser display information only. It does not access your files, camera or microphone.
How to Use the Screen Resolution Test
- Review the screen size shown at the top of the test.
- Compare it with the estimated physical resolution.
- Check the browser viewport to see the usable webpage area.
- Resize or rotate the device and watch the measurements update.
- Use fullscreen to reduce browser interface space.
CSS Pixels vs Physical Pixels
Browsers often report screen dimensions in CSS pixels instead of the exact number of physical panel pixels.
The physical estimate multiplies the reported size by the device pixel ratio. Browser zoom, display scaling and privacy protection can affect the result.
What the Online Screen Resolution Test Checks
The test combines browser-reported screen dimensions, viewport measurements and device pixel ratio to explain how much display space is available to your device and to webpages.
Screen size in CSS pixels
Shows the width and height reported by the browser for the complete screen. These values may differ from the panel's marketed physical resolution.
Estimated physical resolution
Multiplies the reported screen dimensions by device pixel ratio to provide a practical estimate of physical display pixels.
Browser viewport size
Measures the visible webpage area inside the current browser window, excluding interface space outside the page.
Device pixel ratio
Shows how many physical display pixels are commonly used to represent one CSS pixel at the current scaling configuration.
Screen and viewport aspect ratio
Compares width with height and identifies common shapes such as 16:9, 16:10, 21:9, 4:3 and portrait ratios.
Estimated browser refresh rate
Samples animation timing to provide an approximate refresh-rate reading alongside the resolution and display information.
Screen Resolution Terms Explained
Modern browsers separate webpage layout pixels from the physical pixels built into a display. Understanding that distinction helps explain why an online result may not match the number printed on a monitor, laptop, tablet or phone box.
CSS pixels
CSS pixels are the logical units webpages use for layout. Display scaling can make one CSS pixel cover more than one physical panel pixel.
Physical pixels
Physical pixels are the individual picture elements built into the display panel. The browser may not expose their exact count directly.
Device pixel ratio
Device pixel ratio, or DPR, describes the relationship between physical display pixels and CSS pixels at the current scale.
Browser viewport
The viewport is the part of the browser available to webpage content. Tabs, toolbars, side panels and scrollbars can reduce it.
Available screen area
Available screen area excludes operating-system interface regions such as a taskbar, dock or persistent system controls.
Colour depth
Colour depth is the number of bits the browser reports for representing colour. It does not measure display colour accuracy or gamut.
Aspect ratio
Aspect ratio describes the proportional relationship between width and height, independent of the total pixel count.
Display orientation
Orientation identifies whether the current screen is landscape, portrait or square and updates when supported devices rotate.
Common Screen Resolutions Explained
Resolution names are convenient categories rather than guarantees of screen size, sharpness or quality. Pixel density, viewing distance, scaling and panel size also affect how detailed a display appears.
| Category | Resolution | Description |
|---|---|---|
| HD | 1280 × 720 | A common baseline resolution for smaller screens and older displays. |
| Full HD | 1920 × 1080 | Also called 1080p and widely used by monitors, laptops and televisions. |
| QHD | 2560 × 1440 | Also called 1440p and often used for higher-detail desktop and gaming displays. |
| 4K UHD | 3840 × 2160 | Four times the pixel count of Full HD and common on premium displays. |
| 5K | 5120 × 2880 | A high-resolution 16:9 format used by some professional displays. |
| 8K UHD | 7680 × 4320 | A very high-resolution format with four times the pixel count of 4K UHD. |
When to Use a Screen Resolution Tester
Use the live measurements whenever you need to confirm how a browser sees the current display, window size, orientation or scaling configuration.
After connecting a new monitor
Compare the estimated physical resolution with the mode selected in the operating system and the display's specification.
When a website layout looks different
Check the active browser viewport and responsive breakpoint to understand why a mobile, tablet or desktop layout is appearing.
After changing display scaling
Refresh the measurements and compare CSS pixels, physical estimates and device pixel ratio before and after the change.
When testing responsive designs
Resize the browser and watch the viewport dimensions and breakpoint result update without reloading the page.
How Accurate Is an Online Resolution Test?
Screen and viewport values come from standard browser APIs. They describe the values exposed to the current webpage, which is useful for responsive design and browser diagnostics.
The estimated physical resolution is calculated from screen dimensions and device pixel ratio. Operating-system scaling, browser privacy protection, remote desktops, virtual machines and unusual display modes can affect the estimate.
What This Test Cannot Measure
It cannot physically inspect the panel or confirm pixel density, screen size in inches, colour accuracy, HDR capability, response time, input lag or exact hardware refresh timing.
For the monitor's configured signal resolution, verify the operating-system display settings and the manufacturer's specification alongside the browser result.
What Screen Resolution Results Mean
Screen resolution describes the number of pixels available across a display. Higher resolutions can show more detail, although scaling may make the browser report fewer CSS pixels.
The browser viewport is usually smaller than the full screen because browser bars, tabs and operating-system controls use part of the available space.
Resolution Looks Incorrect?
Browser and operating-system scaling can make the displayed result differ from the monitor's advertised specification.
Check display scaling
Operating-system scaling can make a high-resolution display report fewer CSS pixels.
Reset browser zoom
Set browser zoom to 100% before comparing viewport measurements.
Use fullscreen mode
Fullscreen removes browser interface space and increases the available viewport.
Check display settings
Confirm that the operating system is using the monitor's recommended resolution.
Frequently Asked Questions
Is this screen resolution test free?
Yes. The test is free and does not require an account, download or device permission.
Why is my reported resolution lower than expected?
Display scaling and device pixel ratio can make browsers report CSS pixels instead of the display's complete physical pixel count.
What is device pixel ratio?
Device pixel ratio compares physical display pixels with CSS pixels used by webpages.
What is browser viewport size?
Viewport size is the width and height available for webpage content inside the browser window.
Is the refresh-rate result exact?
No. It is an estimate based on browser animation timing and can be affected by power saving or browser limits.
Does fullscreen change my actual resolution?
No. Fullscreen can increase the browser viewport but does not change the monitor's physical resolution.
What is my actual screen resolution?
The screen-size value is what the browser reports in CSS pixels. The estimated physical resolution multiplies that value by device pixel ratio, but the operating-system display settings remain the best place to confirm the configured output resolution.
Why does a 4K screen report 1920 × 1080?
A 4K display using 200% scaling may expose approximately 1920 × 1080 CSS pixels while using a much larger number of physical panel pixels.
Does browser zoom change screen resolution?
Browser zoom does not change the monitor's physical resolution. It can change webpage layout and may affect some viewport-related measurements.
What is the difference between screen size and viewport size?
Screen size describes the complete browser-reported display, while viewport size describes the area currently available to webpage content.
Why is the viewport smaller than the screen?
Browser tabs, toolbars, side panels, window borders, scrollbars and operating-system interface areas can reduce the available webpage area.
Can I test a phone or tablet resolution?
Yes. The measurements work on supported mobile browsers and update when the device rotates or the viewport changes.
What does a device pixel ratio of 2 mean?
It commonly means the display uses approximately two physical pixels along each dimension for one CSS pixel, although browser and operating-system behaviour can vary.
Is screen resolution the same as screen size?
No. Resolution is a pixel dimension, while physical screen size is measured diagonally in inches or centimetres.
Is a higher resolution always better?
Higher resolution can provide more detail, but image quality also depends on panel size, pixel density, scaling, colour, contrast, refresh rate and viewing distance.
Can this test identify ultrawide resolutions?
Yes. The dimensions and aspect-ratio result can identify common ultrawide shapes such as 21:9 and 32:9 when the browser reports corresponding proportions.
Related Device Tests
- Dead Pixel Test — Display solid colours to check for stuck or dead pixels.
- Camera Resolution Test — Check whether your camera supports HD, Full HD or 4K.
- Webcam Test — Check your live camera image, framing and focus.
Check Every Part of Your Device
Work through the complete collection of free browser-based device tests.