Pixels ↔ ratios
Video Aspect Ratio Calculator
Enter a width or height and lock a preset ratio (16:9, 9:16, 1:1, 4:5, 21:9). Get exact pixel dimensions for YouTube, Shorts, TikTok, Reels, and feed posts.
Quick answer
Aspect Ratio Calculator is a free browser tool on Knowlify. Use it below with no signup. Your inputs stay in the browser session. For narrated training videos from documents, use https://create.knowlify.com.
How it works
Three steps, no account
01
Pick a preset
Choose 16:9 for landscape YouTube, 9:16 for Shorts/TikTok/Reels, or 4:5 for Instagram feed.
02
Enter width or height
We calculate the matching side so the frame stays on ratio.
03
Export to your editor
Use the pixel size when you create a new sequence or resize footage.
FAQ
Questions people ask about Aspect Ratio Calculator
Is this aspect ratio calculator free?+
Yes. aspect ratio calculator on Knowlify is free to use with no signup, no watermark, and no account required.
What aspect ratio is YouTube?+
Standard YouTube videos use 16:9 (for example 1920×1080). Shorts use 9:16 (for example 1080×1920).
What size should TikTok or Reels be?+
Use 9:16 vertical, commonly 1080×1920. Avoid letterboxing when you can shoot or crop native vertical.
How do I calculate height from width?+
Pick the ratio, enter width, and the calculator fills height. Or enter height and we fill width.
Do I need an account?+
No. Open the tool, use it in your browser, and download or copy the result.
Does this work on Mac and Windows?+
Yes. It runs in modern desktop browsers (Chrome, Edge, Firefox, Safari). Very large media files need enough device memory.
Need a full video, not just a utility?
Ratios sorted? Generate multi-format training and explainer videos from your docs in Knowlify.