How to check screen resolution, scaling and pixel ratio

Find the measurement you need

A wallpaper uses the display’s physical resolution. A website layout uses the space available in the browser, measured in CSS pixels. Window size, scaling and page zoom affect that space. A 1920 × 1080 and a 2560 × 1440 screen both have a 16:9 ratio. Pixel count alone cannot tell you the size in inches.

Check Windows, macOS and phones

• Windows: Open Settings → System → Display, select the monitor and check resolution and scale separately.
• macOS: Open System Settings → Displays. Scaling presets alter available space. Check the model specifications for native panel resolution.
• Phone: Browser measurements are usually CSS sizes. Check the device specifications for panel resolution or the image properties for the size of a screenshot.

Why 1920 can look like 1536

At 125% scaling, a 1920-pixel-wide display can report approximately 1536 logical pixels. The calculation is 1920 ÷ 1.25. Window size and zoom can change the actual browser reading. At a device pixel ratio of 2, a 400 CSS-pixel image can occupy 800 device pixels, so a larger source may render more sharply.

Try a one-minute experiment

Open Screen Information, resize the window and watch the viewport reading. Change page zoom and compare CSS values again. The display hardware is unchanged. Refresh rate measures updates over time rather than pixel count. Use the operating system’s advanced display settings to check the configured refresh rate.