Aspect Ratio Calculator
Resize dimensions while keeping the aspect ratio, with a visual preview
Change any field and the other side will be calculated automatically in proportion.
Instructions
アスペクト比計算機の使い方
機能概要
画像、動画、キャンバスのサイズを変更するとき、比率が崩れるのが一番の心配です。このツールは元の比率を保ったままもう片方のサイズを換算し、簡約した比率も表示します。
使用方法
注意事項
❓ FAQ
Why calculate the ratio before resizing?
Stretching only the width or height distorts the image. Calculating the other side from the ratio keeps the image undistorted, which is exactly what the "keep aspect ratio" button does in image editing software.
What are common 16:9 sizes?
Common ones include 1920×1080, 1280×720, 2560×1440 and 3840×2160. Enter 1920 and 1080 as the original width and height, then set the new width to the value you want.
Which ratio is used for vertical videos?
The common vertical ratio for short videos is 9:16, for example 1080×1920 and 720×1280. Just click the 9:16 button to apply it.
🔗 Related Tools
📝 Related Articles
How to Use a Cron Expression Generator: Complete Beginner Steps
Use an online tool to select the five time fields, automatically generate a standard Cron expression with a human-readable time explanation, and learn to troubleshoot execution time deviations caused by time zones and field counts, so complex schedules no longer rely on guesswork.
tool-tutorialsHow to Use an Online CSV to JSON Tool: Beginners Can Get Started in Three Steps
Use a three-step process to complete an online CSV to JSON tool operation, covering option settings, result validation, error troubleshooting, large file handling, mobile operation, and API debugging scenarios. Beginners can follow along to get usable JSON data.
tool-tutorialsWhat Is HTML Formatting? A Beginner's Guide to the Key Points
Use a browser-based HTML formatting tool that runs locally to restore compressed or messy HTML into an indented, readable structure. Also understand the difference between formatting and minification, the troubleshooting order for messed-up indentation, and how to handle large files getting stuck and mobile no-install solutions.
tool-tutorialsThe Difference Between JS Formatting/Minification and Manual Code Cleanup: Which Is More Suitable
The difference between JS formatting/compression and manual cleanup comes down to automation versus human judgment. Formatting and compression are handled in bulk by tools according to rules—fast and consistent; manual cleanup is more flexible, suited to scenarios with special naming conventions or complex logic. For everyday development and debugging, use tools first and save human effort for the parts that truly need judgment. Understanding what JS formatting and compression means helps you decide when to use it and when to stop.