Aspect Ratio Calculator — Aspect ratio describes the proportional relationship between width and height. It is the magic number behind "why does this photo look squished?" and "what resolution do I need for an Instagram Reel?".
All math runs locally. No image is uploaded.
Was Aspect Ratio Calculator useful?
O que é Aspect Ratio Calculator?
Aspect ratio describes the proportional relationship between width and height. It is the magic number behind "why does this photo look squished?" and "what resolution do I need for an Instagram Reel?".
Enter any two dimensions and the tool reduces them to their simplest ratio (e.g. 1920×1080 → 16:9). You can then resize to a target width, fit inside a maximum box, or look up common preset ratios for social media, print, and video.
Como usar
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Enter width and height
In any unit — pixels, mm, inches. The ratio is unitless.
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Read the reduced ratio
The tool uses the GCD of width and height to show the cleanest form.
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Resize or fit
Pick a target width or max bounds to see the new dimensions.
Exemplos
1920×1080 video
Full HD video, reduced.
Resultado: 16:9
1080×1920 Reel
Vertical video for Instagram Reels / TikTok.
Resultado: 9:16
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Last reviewed: 2026-09-25