Image Resize Calculator
Enter an image's original dimensions and either a target width or height to instantly see the other dimension, maintaining the original aspect ratio. Also calculates new file size estimate based on scaling factor, new resolution in megapixels, and the percentage change. Works for any image format.
Ctrl+Enter to run · Ctrl+K to switch tools · Recent button shows input history
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How is the estimated file size calculated?
File size scales roughly with pixel count (width × height). The estimate assumes a proportional relationship — JPEG compression artifacts and metadata are not accounted for.
Can I use this for video resolutions?
Yes — the aspect-ratio maths is the same for video. Enter the original frame size and target width/height to find the other dimension.
What is aspect ratio lock?
Aspect ratio lock means if you change width, height updates automatically (and vice versa) to maintain the original proportions. This tool always applies aspect ratio lock.