Aspect Ratio Calculator
Calculate width, height, and ratio for video, image, and screen sizes
使い方
- 1Pick a preset or enter a ratio
16:9 for YouTube, 9:16 for TikTok/Shorts/Reels, 1:1 for Instagram feed, 4:5 for Instagram portrait.
- 2Enter a known dimension
Type the width you have - the calculator fills in the matching height (and vice versa).
- 3Read the ratio and pixel plan
The tool shows the exact ratio, GCD-reduced form, and a copy-ready width×height pair.
Aspect Ratio Calculator について
Free aspect ratio calculator. Enter any two of width, height, or ratio to get the third - perfect for resizing video, cropping images, or planning responsive layouts. Includes presets for 16:9, 9:16 (vertical), 1:1, 4:3, 21:9 (cinematic), and every social platform. 712 Tools の Aspect Ratio Calculator はモダンな JavaScript API を使って完全にブラウザ内で動作します - サーバーがあなたのデータを見ることは一切ありません。つまり、即時の結果、完全なプライバシー、アップロード制限なしです。
デバッグ、簡単な確認、あるいは本番のインシデント対応まで - このツールは何度でも無料で使えます。ウォーターマークなし、サインアップなし、ツール内広告なし。
よくある質問
What ratio is a YouTube video?
16:9 for standard videos, 9:16 for Shorts, and 4:3 for very old uploads. 4K, 1080p, and 720p all share the same 16:9 aspect.
TikTok, Reels, Shorts - which ratio?
All three use 9:16 (portrait), typically 1080×1920. Anything else gets letterboxed or cropped.
How do I keep aspect when resizing?
Enter your original width and height, then change either dimension - the calculator updates the other to preserve the ratio.
What's 21:9?
The 'cinematic' or ultrawide ratio (e.g. 2560×1080). Common for film and ultrawide monitors - some creators letterbox to 21:9 for a cinematic feel.
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