What is a 16:9 aspect ratio?

16:9 is the universal standard for high-definition displays, including monitors, TVs, and mobile devices. For every 16 units of width, there are 9 units of height.

What ratio is an Ultrawide monitor?

Most Ultrawide monitors use a 21:9 aspect ratio, which provides a significantly wider field of view compared to standard widescreen monitors.

Aspect Ratio Checker — Online Screen Ratio & Resolution Tester

📅Published: February 22, 2026👤Author: FPS Tools Team

Automatically detect your screen's aspect ratio and check for scaling issues. Verify if your display is 16:9, 21:9 Ultrawide, or 4:3 Legacy.

Detected Aspect Ratio

Detecting...

Resolution: 0 x 0
Device Pixel Ratio: 1x

Standard Reference Ratios

16:9 - Modern Widescreen (Standard)(1.78)

21:9 - Ultrawide (Cinema)(2.33)

32:9 - Super Ultrawide(3.56)

4:3 - Legacy / Tablet(1.33)

16:10 - Productivity Laptop(1.60)

1:1 - Square(1.00)

Geometric Scaling Test

If the circle below is not perfectly round, your display is stretching pixels.

Perfectly Round?
Circle Test

What is Aspect Ratio?

Aspect ratio is the proportional relationship between a display's width and its height. It is typically expressed as two numbers separated by a colon, such as 16:9.

Common Display Ratios

16:9 (Widescreen): The standard for most monitors, TVs, and modern YouTube videos.
21:9 (Ultrawide): Popular for immersive gaming and cinematic movies without black bars.
32:9 (Super Ultrawide): Equivalent to two 16:9 monitors side-by-side.
4:3 (Full Screen): The legacy standard for CRTs and older television broadcasts.

How to Use This Checker

Automatic Detection: The card below shows your current screen's resolution and calculated ratio.
Scaling Circle: Look at the circle in the test area. If it appears as an oval (stretched horizontally or vertically), your display resolution might not be native, or your scaling settings are incorrect.
Fullscreen Test: Use the fullscreen button to verify the ratio across your entire panel without browser UI interference.

Frequently Asked Questions

Why does my screen look stretched?

This usually happens if your operating system resolution doesn't match your monitor's physical pixel count. For example, setting a 1920x1080 resolution on a 2560x1080 (Ultrawide) monitor will stretch the image.

What is 21:9 in pixels?

The most common resolutions for 21:9 are 2560x1080 (WFHD) and 3440x1440 (WQHD).