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RapideTools

Calculateur de ratio d'aspect

Trouvez la largeur ou la hauteur depuis un ratio.

Pick an aspect ratio (or enter a custom one) and a width or height to instantly get the matching dimension. Useful for images, videos, thumbnails and social media assets. Everything runs locally in your browser.

Votre saisie est traitée localement dans votre navigateur — rien n'est envoyé, stocké ni journalisé.

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Comment ça marche

  1. 1 Choose a ratio, or enter a custom one.
  2. 2 Type a width or a height.
  3. 3 The matching dimension is filled in automatically.

Cas d'usage courants

  • Size a 16:9 video or thumbnail.
  • Fit images to a social media ratio.
  • Plan a 21:9 banner.
  • Resize while keeping proportions.

Questions fréquentes

Is my input sent to a server?

No. Every calculation runs locally in your browser — your input is never uploaded, stored or logged.

How is the missing side calculated?

From the ratio: height = width × ratioH ÷ ratioW (and the reverse). For 16:9, a width of 1920 gives a height of 1080.

Can I use a custom ratio?

Yes — choose Custom and enter any width:height ratio.

Is it really free?

Yes — free, with no signup and no limits.