Calculate video aspect ratios, find missing dimensions, and get crop sizes for YouTube (16:9), TikTok (9:16), Instagram, and more. Instant, browser-based.
Common aspect ratios
⚡ Skip the manual steps
Upload once. Get a transcript, speaker labels, and subtitles.
Aspect ratio describes the proportional relationship between a video's width and height, expressed as two numbers separated by a colon — for example, 16:9. It defines the shape of the frame, not the actual pixel dimensions. A 1920×1080 video and a 1280×720 video are both 16:9 because they share the same proportional relationship. Aspect ratio affects how your video appears on different screens and platforms, and choosing the wrong one can result in black bars, cropping, or distortion when your content is displayed.
16:9 is the universal standard for YouTube, TV, and most desktop players. 9:16 (vertical) is the native format for TikTok, Instagram Reels, and YouTube Shorts. 1:1 (square) works well in social media feeds and retains more screen space on mobile than 16:9. 4:5 (portrait) is Instagram's recommended format for feed videos because it takes up maximum vertical space without going fully vertical. 21:9 (ultrawide) is used in cinematic productions for a widescreen theatrical feel. Knowing which ratio suits your platform avoids wasted space and re-editing.
When a video's native aspect ratio does not match the player or platform, one of two things happens: letterboxing adds black bars on top and bottom (for widescreen content in a square player) or pillarboxing adds black bars on the sides (for square content in a widescreen player). Some platforms automatically crop the video to fill the frame, cutting off part of the image. To avoid surprises, always check the required aspect ratio for your target platform before shooting or exporting, and use this calculator to confirm your dimensions before editing.
Detect mode: enter width and height
Type your video's pixel dimensions to see its aspect ratio and how it compares to common formats.
Calculate mode: enter a ratio and one dimension
Select a standard ratio (16:9, 9:16, etc.), enter width OR height, and the tool calculates the other dimension.
Use the result
Use the output dimensions to set up your video editor, export settings, or crop parameters.