Free tool
Aspect ratio calculator
Pick a named ratio like 16:9 or 9:16, or type a width and height, to see the simplified aspect ratio and the pixel sizes people export most often. Free, no sign-up, and nothing is uploaded.
YouTube, Vimeo, help-center embeds, most tutorial videos
How to calculate an aspect ratio
- 1
Pick a ratio or type sizes
Choose 16:9, 9:16, 1:1 and other presets, or enter a width and height to see the simplified ratio.
- 2
Lock one side
Change the width and the height follows the ratio, or the other way around. Pixel sizes stay whole numbers.
- 3
Grab a common size
Tap 1920×1080, 1280×720, 1080×1920 and other export sizes that match the ratio.
- 4
Copy and use it
Copy the ratio or the pixel size into your editor, export settings or thumbnail tool.
Aspect ratio chart
Common video and social ratios
The sizes people export most often. Tap a row in the calculator to load it, or use these as a reference when you set up a project.
| Ratio | Example size | Typical use |
|---|---|---|
| 16:9 | 1920×1080 | YouTube, Vimeo, help-center embeds, most tutorial videos |
| 9:16 | 1080×1920 | YouTube Shorts, TikTok, Instagram Reels, vertical stories |
| 1:1 | 1080×1080 | Instagram feed posts, profile images, square social cuts |
| 4:5 | 1080×1350 | Instagram portrait posts; YouTube's auto crop for vertical with a 16:9 thumb |
| 4:3 | 1440×1080 | Older presentations, some LMS players, classic camera footage |
| 21:9 | 2560×1080 | Ultrawide monitors, cinematic banner clips |
| 2:1 | 1920×960 | Some blog headers and Open Graph images |
| 3:2 | 1620×1080 | Still photography crops and some slide decks |
Tips for picking a video size
Match the player your audience uses, then pick a resolution that keeps text sharp.
Tutorials are almost always 16:9
Help centers, YouTube and most LMS players expect widescreen. Export 1920×1080 unless you know you need something else.
Shorts and Reels are 9:16
1080×1920 is the usual export. A 16:9 video cropped to 9:16 loses the sides, so shoot or render vertical when that's the goal.
Don't stretch to fit
Changing only one side without keeping the ratio squashes the picture. Crop or letterbox instead.
Need a thumbnail next?
The YouTube thumbnail resizer crops any image to 16:9 or 9:16 and keeps it under 2 MB.
From app to video
Need the video itself? Let SayScreen make it
SayScreen makes narrated tutorials of your web app from one sentence. The AI drives a real browser, writes and voices the narration, and edits in zooms, a gliding cursor and captions.
You get an MP4 at 1080p and 60 fps, in widescreen (16:9) or vertical (9:16), plus an .srt caption file. See also the video file size calculator when you need to fit an upload limit.
Frequently asked questions
The relationship between a video's width and height, written as two numbers with a colon, like 16:9. It describes the shape, not the resolution: 1280×720 and 1920×1080 are both 16:9.
16:9 for standard videos (1920×1080 is the usual export). YouTube Shorts use 9:16, typically 1080×1920. Mixing them means YouTube will letterbox or crop.
Divide the width and height by their greatest common divisor. 1920×1080 divides by 120 to give 16:9. This tool does that when you enter width and height.
Any size where width ÷ height equals 16 ÷ 9. Common exports are 1280×720 (720p), 1920×1080 (1080p) and 3840×2160 (4K). Smaller 16:9 sizes like 640×360 still keep the same shape.
1080×1920 is the standard. 720×1280 also works when you need a lighter file. Keep important text away from the top and bottom edges, where platform UI sits.
Use 16:9 for almost every modern tutorial, demo and YouTube upload. 4:3 is an older TV and presentation shape; only pick it when a player or course platform requires it.
No. The calculator runs as arithmetic in your browser. Nothing you type leaves the page.
Something missing or not working? hey@sayscreen.com
Skip the recording. Describe the lesson instead.
Point SayScreen at your app, say what to teach, and get a narrated, edited video back.
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