Convert images to 1:1, 16:9, 4:3, or any custom ratio with letterbox, crop, or stretch modes.
Upload your image.
Select a target aspect ratio preset (1:1, 16:9, etc.) or enter custom W:H values.
Choose a fit mode: Letterbox (adds padding), Crop (fills frame), or Stretch.
For Letterbox mode, pick a background colour.
Set the output width and click Download.
Letterbox fits your entire image inside the target frame and fills empty space with background colour. Crop fills the entire frame by zooming in and cutting off the edges.
Yes! Select the 1:1 preset, choose Letterbox mode with a white or black background, and download.
Every platform has its preferred image dimensions. Instagram posts want 1:1 squares. YouTube thumbnails need 16:9. Facebook covers are 820×312 (roughly 2.6:1). Twitter headers are 3:1. When your original photo doesn't match, you need to adapt it — but simply squashing or stretching it looks terrible.
This Image Aspect Ratio Fixer gives you three intelligent fitting modes: Letterbox (add colored padding to fill the frame), Crop (zoom in and cut the edges), and Stretch (distort to fill). Combined with preset ratios for every major platform and a custom input option, it handles any formatting challenge in seconds — entirely in your browser with no uploads.
An aspect ratio is simply the proportional relationship between width and height, expressed as W:H.
| Platform | Ratio | Example Size |
|---|---|---|
| Instagram Post | 1:1 | 1080×1080 |
| Instagram Story | 9:16 | 1080×1920 |
| YouTube Thumbnail | 16:9 | 1280×720 |
| Facebook Cover | ~2.6:1 | 820×312 |
| Twitter Header | 3:1 | 1500×500 |
| Standard Photo | 4:3 | 1200×900 |
The three fit modes explained:
Letterbox: The image is scaled proportionally to fit inside the target frame. Whatever space remains is filled with the chosen background color (white, black, blur, or custom).
scale = min(targetW / imgW, targetH / imgH)
offsetX = (targetW - imgW * scale) / 2
offsetY = (targetH - imgH * scale) / 2
The offset centers the scaled image. Background fills the rest.
Crop: The image is scaled proportionally to fill the target frame, then the overflow is clipped.
scale = max(targetW / imgW, targetH / imgH)
offsetX = (targetW - imgW * scale) / 2 // negative = clipped
offsetY = (targetH - imgH * scale) / 2 // negative = clipped
The center of the image is preserved. Edges are cut off.
Stretch: The image is drawn to exactly fill the target dimensions regardless of its original ratio:
ctx.drawImage(img, 0, 0, targetW, targetH)
Simplest calculation, but produces visible distortion for significant ratio differences.
All three modes are implemented via the HTML5 Canvas API, drawing and exporting entirely in the browser.
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Converts images to any aspect ratio with letterbox, crop, or stretch modes.
JPG, PNG, WebP supported