How to check your screen resolution
- Open the page. Screen resolution (native, estimated) shows the hardware pixels on your display, such as 1920 × 1080. No clicks or permissions are needed.
- Read the note under it. It lists what your browser reports in CSS pixels and the pixel ratio used to reach the native figure.
- Resize the window or drag it to another monitor. The viewport, breakpoint match and ratio update within a fraction of a second.
- Type your Screen diagonal (inches) to get pixels per inch and the panel's physical size.
- Press Copy all details to put every row on the clipboard for a bug report or support ticket.
How the numbers are worked out
Browsers report screen width and height in CSS pixels, not hardware pixels. The device pixel ratio is the number of hardware pixels per CSS pixel, so native resolution is the CSS width times the ratio by the CSS height times the ratio, each rounded. PPI is the diagonal in pixels, the square root of width squared plus height squared, divided by the diagonal in inches. The CSS DPI row is only 96 times the ratio, a reference value rather than your panel's real density. Breakpoints are Tailwind's defaults, tested as min-width media queries against your viewport width.
Worked example
A laptop whose browser reports 1536 × 864 CSS pixels at a pixel ratio of 1.25 gets 1536 × 1.25 = 1920 and 864 × 1.25 = 1080. The top line reads 1920 × 1080, labeled "Full HD (1080p), 16:9", and Display scaling and zoom reads 125%. Entering 15.6 as the diagonal gives about 141 PPI, because the diagonal is 2,203 pixels and 2,203 ÷ 15.6 = 141, with a panel of roughly 13.6 × 7.6 in (34.5 × 19.4 cm).
Limits and edge cases
- The native figure multiplies rounded values, so it can be a pixel or two off, mostly on Android phones with fractional ratios such as 2.625.
- Browser zoom changes the pixel ratio and the CSS pixel numbers. If a reading looks odd, reset zoom with Ctrl+0 (Cmd+0 on a Mac).
- Privacy modes, such as Firefox's fingerprinting protection, can report rounded or made-up sizes. Color depth is usually 24-bit even on 10-bit or HDR panels.
- With several monitors, the values describe the screen holding this window. Nothing is sent anywhere.
- To simplify a pixel size into a ratio use the aspect ratio calculator. To resize a wallpaper to your screen use the image resizer, and for browser and device details try the user agent parser.
Frequently asked questions
Why do other tools show a smaller resolution than this one?
Many tools print the CSS pixel size. When Windows or macOS scales the interface, a 1920 × 1080 display reports a smaller number, for example 1536 × 864 at 125%. This page multiplies by the pixel ratio to show the hardware resolution that your display settings list.
What is the difference between screen resolution and viewport size?
Screen resolution is the pixel count of the whole display. The viewport is the part of the browser window that shows the page, so it excludes the tab strip, address bar and taskbar, and it changes whenever you resize the window.
Is the DPI shown the real pixel density of my monitor?
No. Browsers cannot read the physical size of a display, so the CSS DPI row is only 96 times the pixel ratio. For true pixel density, enter your diagonal in the PPI box.
How do I change my screen resolution?
This page only reads it. On Windows open Settings, System, Display and use Display resolution. On a Mac open System Settings and choose Displays. The recommended or default setting matches the native resolution and looks sharpest.