Aspect ratio is the proportional relationship between an image's width and height, written as width:height. It stays the same no matter the pixel size — a 1600×900 photo and an 800×450 photo are both 16:9.

Common ratios and where they're used

  • 16:9 — video, YouTube thumbnails, most screens.
  • 4:3 — older cameras, presentations, some print.
  • 1:1 — square; Instagram posts, avatars, product shots.
  • 9:16 — vertical; Stories, Reels, TikTok.

How to change an image's ratio

You can't just stretch — that distorts faces and logos. Crop to the new shape instead. Use the crop tool to cut to the exact ratio, or the resize tool to hit precise pixel dimensions.

Tips

  • Decide the target ratio before cropping so you don't lose important edges.
  • For social presets and exact pixel sizes, see our resize guides. Related reading: DPI vs PPI.