Image Tools March 20, 2025 4 min read

How to Crop Images Online with Aspect Ratio Lock

Need a perfect square for your profile picture? A 16:9 banner for YouTube? Crop any image to exact dimensions with locked aspect ratios —no Photoshop needed.

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Common Aspect Ratios Explained

  • 1:1 (Square) —Instagram posts, profile pictures, app icons. The most universally useful crop.
  • 4:3 —Standard photo ratio, presentations (4:3 slides), older TVs and monitors.
  • 16:9 —YouTube thumbnails, video covers, desktop wallpapers, widescreen displays.
  • 3:2 —Classic DSLR photo ratio, print photos (46 inches), film photography.
  • Free crop —Custom dimensions for any specific requirement.

How to Crop with ToolKnit

  1. Open the tool —Go to Crop Image.
  2. Upload your image —Drag and drop or click to browse.
  3. Select aspect ratio —Choose 1:1, 4:3, 16:9, 3:2, or Free.
  4. Adjust the crop area —Drag to position, resize the selection box.
  5. Export —Download your cropped image as lossless PNG.

Pro tip: For social media profile pictures, always use 1:1 (square) at the highest resolution possible. Most platforms downscale but never upscale.

Platform-Specific Sizes

Social Media

  • Instagram post —1:1 (10801080px) or 4:5 (10801350px)
  • Instagram Story —9:16 (10801920px)
  • Facebook cover —820312px (approximately 2.6:1)
  • Twitter/X banner —1500500px (3:1)
  • LinkedIn banner —1584396px (4:1)

Video Platforms

  • YouTube thumbnail —16:9 (1280720px)
  • TikTok cover —9:16 (10801920px)

Why Lossless PNG Output?

Our crop tool exports as PNG to ensure zero quality loss. The cropped image is pixel-perfect with no compression artifacts. If you need a smaller file size after cropping, use our Compress Image tool or convert to JPG.

Privacy

All processing happens in your browser. Your images never leave your device.

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