Aspect Ratio Test
Detect your display's aspect ratio and see how it compares to common standards.
16:9
Standard Widescreen
16:10
WUXGA / MacBook
21:9
Ultra-wide
32:9
Super Ultra-wide
Testing guide
How to check your screen aspect ratio
Aspect ratio is the proportional relationship between screen width and height, expressed as a ratio like 16:9. It determines whether video fills your screen or shows black bars, and whether games render the field of view the way the developer intended.
Best for
- Identifying the exact aspect ratio of an unfamiliar display.
- Working out why video shows black bars on the sides or top and bottom.
- Checking that an ultrawide monitor is reporting its true ratio rather than a scaled one.
How to run the test
- 1Open the page on the display you want to identify.
- 2Compare the detected ratio against the common standards shown alongside it.
- 3If the ratio looks unusual, confirm the system is running at the panel native resolution.
- 4Note the pixel dimensions as well, since two displays can share a ratio at very different resolutions.
How to read the result
16:9 is the standard widescreen ratio used by most monitors, TVs and video content.
21:9 and 32:9 are ultrawide and super-ultrawide, which fill more of your peripheral vision but cause pillarboxing on 16:9 video.
A non-standard ratio usually means the system is not at native resolution rather than an unusual panel.
Related tools and guides
Frequently asked questions
What aspect ratio is my monitor?
Most desktop monitors and laptops are 16:9. Some productivity and MacBook panels use 16:10, which is slightly taller. Ultrawides are 21:9, super-ultrawides are 32:9, and older or specialist displays may be 4:3 or 3:2.
Why does my video have black bars?
Because the video aspect ratio does not match your screen. Many films are shot at 2.39:1, which is wider than 16:9, so you get bars above and below. Playing 16:9 content on a 21:9 ultrawide produces bars on the left and right instead.
What is the difference between 16:9 and 16:10?
16:10 is proportionally taller, giving roughly 11 percent more vertical space at the same width. That extra height is useful for documents, code and timelines, which is why it is common on productivity monitors and MacBooks, but it means bars on 16:9 video.
Is an ultrawide monitor better than two monitors?
It depends on the work. An ultrawide gives one continuous surface with no bezel in the middle, which suits video timelines and wide spreadsheets. Two separate monitors give more total area and let you put one in portrait, which suits reading and reference work.
Why is my aspect ratio showing an unusual number?
Almost always because the system is not running at the panel native resolution, so the reported pixel dimensions do not reduce to a standard ratio. Set the display back to its recommended resolution and check again.
Testing guide
How to check your screen aspect ratio
Aspect ratio is the proportional relationship between screen width and height, expressed as a ratio like 16:9. It determines whether video fills your screen or shows black bars, and whether games render the field of view the way the developer intended.
Best for
- Identifying the exact aspect ratio of an unfamiliar display.
- Working out why video shows black bars on the sides or top and bottom.
- Checking that an ultrawide monitor is reporting its true ratio rather than a scaled one.
How to run the test
- 1Open the page on the display you want to identify.
- 2Compare the detected ratio against the common standards shown alongside it.
- 3If the ratio looks unusual, confirm the system is running at the panel native resolution.
- 4Note the pixel dimensions as well, since two displays can share a ratio at very different resolutions.
How to read the result
16:9 is the standard widescreen ratio used by most monitors, TVs and video content.
21:9 and 32:9 are ultrawide and super-ultrawide, which fill more of your peripheral vision but cause pillarboxing on 16:9 video.
A non-standard ratio usually means the system is not at native resolution rather than an unusual panel.
Related tools and guides
Frequently asked questions
What aspect ratio is my monitor?
Most desktop monitors and laptops are 16:9. Some productivity and MacBook panels use 16:10, which is slightly taller. Ultrawides are 21:9, super-ultrawides are 32:9, and older or specialist displays may be 4:3 or 3:2.
Why does my video have black bars?
Because the video aspect ratio does not match your screen. Many films are shot at 2.39:1, which is wider than 16:9, so you get bars above and below. Playing 16:9 content on a 21:9 ultrawide produces bars on the left and right instead.
What is the difference between 16:9 and 16:10?
16:10 is proportionally taller, giving roughly 11 percent more vertical space at the same width. That extra height is useful for documents, code and timelines, which is why it is common on productivity monitors and MacBooks, but it means bars on 16:9 video.
Is an ultrawide monitor better than two monitors?
It depends on the work. An ultrawide gives one continuous surface with no bezel in the middle, which suits video timelines and wide spreadsheets. Two separate monitors give more total area and let you put one in portrait, which suits reading and reference work.
Why is my aspect ratio showing an unusual number?
Almost always because the system is not running at the panel native resolution, so the reported pixel dimensions do not reduce to a standard ratio. Set the display back to its recommended resolution and check again.