How to use the screen resolution and device info
- Open the page. Your screen size is shown at once.
- Read the table of screen, viewport, window, pixel ratio, color depth, orientation and touch details.
- Resize the window, rotate your device or change the browser zoom and watch the values update.
- Press Copy details to copy the table as text.
What each number means
The screen size is the width and height of your display in CSS pixels, which is the unit web pages use. It is not always the number of physical pixels. A display with a device pixel ratio of 2 packs four physical pixels into each CSS pixel, so a laptop reported as 1,440 by 900 can have 2,880 by 1,800 physical pixels. The page shows that estimate by multiplying the screen size by the ratio.
The usable screen area leaves out bars the system keeps for itself, such as a taskbar or menu bar. The viewport is the part of the window that holds the page, and the window is the whole browser window including its frame. Zooming the page changes the pixel ratio and the viewport but not the screen size.
Aspect ratio and orientation
The aspect ratio is the width over the height, reduced to the smallest whole numbers. 1,920 by 1,080 reduces to 16:9, and 1,440 by 900 reduces to 8:5. Sizes that do not reduce neatly, such as 1,366 by 768, show as 683:384, so the decimal ratio is shown beside it. For working with ratios and image sizes, try the aspect ratio calculator and the image DPI and print size calculator. The TV size and viewing distance calculator helps choose a screen for a room.
Where the numbers come from
Every value is read from your browser with standard screen and window properties. Nothing is looked up, nothing is sent, and the page does not try to identify you. Some browsers round or hide values for privacy, and a few report the device pixel ratio in steps. If a value shows as not available or looks off, the browser is the source. The keyboard tester checks another part of your setup.
Assumptions and limits
- Values come from browser screen and window properties and may be rounded or hidden by the browser.
- Sizes are in CSS pixels. The device pixel estimate multiplies by the pixel ratio.
- The aspect ratio is reduced by the greatest common divisor.
- Nothing is sent anywhere.
Frequently asked questions
How do I find my screen resolution?
Open this page and read the screen size at the top. It shows the width and height of your display in CSS pixels, with an estimate in physical pixels below.
Why is the number different from my display's spec?
Web pages report CSS pixels. A high-density display packs several physical pixels into each CSS pixel, so the reported size is smaller than the physical one.
What is the device pixel ratio?
It is the number of physical pixels for each CSS pixel. Browser zoom changes it, so it can change while you use the page.
Does this tool identify me?
No. It only reads display properties and shows them to you. Nothing is sent or stored.