How the Aspect Ratio Crop Calculator Works
Enter your original image dimensions in pixels and select or type the target aspect ratio. The calculator determines the largest possible crop area that fits the target ratio within your original image, centered both horizontally and vertically. It reports the crop dimensions, the offset from the top-left corner, the percentage of the original image retained, and the resulting megapixel count.
When the target ratio is wider than the original, the full width is used and the height is cropped. When the target ratio is narrower, the full height is used and the width is cropped. This ensures maximum resolution is preserved in the cropped output.
Common Aspect Ratios for Photography
The 3:2 ratio is the standard for full-frame and APS-C cameras, matching standard 4x6 inch prints. The 4:3 ratio is used by Micro Four Thirds cameras and most smartphones. The 16:9 ratio is the standard for video and widescreen displays. The 1:1 square format is popular on social media. The 5:4 ratio matches the popular 8x10 inch print size. Understanding these ratios helps you plan compositions with your intended output in mind.
Social Media Aspect Ratios
Each platform has preferred dimensions: Instagram feed posts work best at 4:5 portrait, Instagram Stories and Reels use 9:16, Facebook posts prefer 1.91:1 landscape, Twitter/X images work at 16:9, and Pinterest pins perform best at 2:3 portrait. Knowing the target ratio before shooting allows you to compose with cropping in mind.
Frequently Asked Questions
What aspect ratio should I use for Instagram?
Instagram supports 1:1 (square), 4:5 (portrait, recommended for feed), 1.91:1 (landscape), and 9:16 (Stories/Reels).
What is the standard aspect ratio for photos?
The most common ratios are 3:2 (full-frame cameras), 4:3 (Micro Four Thirds, smartphones), and 16:9 (video).
How much image is lost when cropping?
It depends on the difference between the original and target ratios. Cropping 3:2 to 1:1 removes about 33% of the pixels.
What aspect ratio is best for printing?
Common print ratios include 3:2 for 4x6, 5:4 for 8x10, 7:5 for 5x7, and 4:3 for 6x8 prints.
How do I calculate crop dimensions for a custom ratio?
Keep the constraining dimension at full size and calculate the other: if target is wider than original, use full width and crop height.