Smarter video starts here! Explore tools for previews, smart cropping, and image-to-video creation. Explore the Q4 launch →
Imgix APIsVideo APISizeAspect Ratio

Aspect Ratio

ar

Standard render

Specifies the output aspect ratio instead of pinning both pixel dimensions. Written as W:H (e.g. 4:5). Also accepts WxH, W,H, or a bare decimal ratio (e.g. 1.85 → 1.85:1).

ar works with fit=crop, fit=fill, and fit=smart-crop. It is ignored for scale, clip, and max.

How the missing dimension is resolved depends on what else you specify:

  • ar + one of w/h — the other dimension is derived from the ratio. ar=4:5&w=400 → 400×500.
  • ar + both w and h — the pair is treated as a bounding box; the output is the largest rectangle of the requested ratio that fits inside it.
  • ar alone — the source is reframed (cropped for fit=crop/smart-crop, padded for fit=fill) to the ratio at its native resolution.
SizeCrop Gravity