Aspect Ratio Calculator
Calculate proportional dimensions and aspect ratios (16:9, 9:16, 4:3, 1:1, 21:9) with automatic width and height scaling.
16:9
1920 × 1080 px
Ratio
16:9
Decimal
1.7778
Megapixels
2.07 MP
Resolutions for 16:9
| Resolution | Width | Height | Pixels |
|---|---|---|---|
| 4K UHD | 3840 | 2160 | 8.3 MP |
| 1440p QHD | 2560 | 1440 | 3.7 MP |
| 1080p FHD | 1920 | 1080 | 2.1 MP |
| 720p HD | 1280 | 720 | 0.9 MP |
| 480p SD | 854 | 480 | 0.4 MP |
| 360p | 640 | 360 | 0.2 MP |
Dimensions
Common Ratios
About
Use this free online aspect ratio calculator for video, photos and social posts. Type a width and a height in pixels, and the tool shows the simplified ratio, such as 16:9 or 4:5, with its decimal value and megapixel count. A 1920 by 1080 frame, for example, simplifies to 16:9.
Choose one of ten common ratios, from 16:9 and 9:16 to 4:3, 1:1, 4:5, 21:9 and 3:2, and the height updates from the width you typed. Turn on the lock to keep the ratio of the last preset you picked (16:9 when you first open the tool) while you change one side. Swap flips width and height, which is the quickest way to go from a landscape frame to a portrait one.
The calculator works only with the numbers. It does not open or change any file, so you can plan a frame size before you export or edit a video or image.
How to use the Aspect Ratio Calculator
- 1
Enter a size
Type a width and a height in pixels under Dimensions. The preview box and the Ratio, Decimal and Megapixels figures update as you type.
- 2
Pick a common ratio
Click a ratio under Common Ratios, such as 9:16 for vertical video, and the height updates to match the width you typed.
- 3
Lock or swap the sides
Click Unlocked to turn the lock on, so one side follows the other. Click Swap to exchange width and height.
- 4
Read the resolutions
The Resolutions table lists 4K UHD, 1440p QHD, 1080p FHD, 720p HD, 480p SD and 360p, with the pixel count of each. Use it to compare sizes before you choose an export resolution.
What people use it for
Sizing a vertical video
Pick 9:16 for vertical video on Shorts or Reels, or 4:5 for an Instagram portrait post, and check the height the tool gives you.
Cropping a photo to a shape
Find the height that matches a set width for a 3:2 photo or a 4:3 frame before you crop.
Planning a frame before you shoot
Check the shape and pixel count of a planned frame, such as 3840 by 2160 for 4K, before you set the camera or the export size.
Comparing resolutions
Compare the megapixel count of 1080p, 1440p and 4K to see how many more pixels each one holds.
Questions
What is an aspect ratio?
An aspect ratio is the proportion of a frame's width to its height, written as two numbers such as 16:9. A 1920 by 1080 frame has the ratio 16:9, because both sides divide by 120.
What aspect ratio should I use for YouTube Shorts or Instagram Reels?
Use 9:16, the vertical ratio, for full-screen Shorts and Reels. Pick it under Common Ratios and check the height the tool gives you for your width.
What aspect ratio is 1920 x 1080?
1920 by 1080 simplifies to 16:9, the standard widescreen ratio. Its decimal value is 1.7778, which is the width divided by the height.
How do I keep the same shape when I resize?
Turn on the lock under Dimensions and change either side. The other side follows the ratio of the last preset you picked, which is 16:9 when you first open the tool.
Does this tool change my video or image?
No. It works only with the numbers you type and does not open or change any file. Resize your file in your editor or export tool, using the width and height from the calculator.