βοΈ Aspect Ratio Crop Calculator
Enter your original dimensions and target ratio to get exact crop dimensions in pixels.
Maximum crop dimensions at the selected ratio
How to Use This Calculator
Every photo has two numbers that matter when you crop: the pixel dimensions of the original file and the aspect ratio you want to end up with. This calculator takes both and returns the largest possible crop in exact pixels, so you know precisely how much resolution you keep before you ever open an editor. Pick a preset ratio or enter a custom one, and the results update instantly.
Enter the Original Width and Height of your photo in pixels. On most cameras you can find this in the file info panel or by checking the image properties. A 24 MP camera typically shoots 6000 x 4000.
Choose a Target Aspect Ratio from the presets: square and 4:5 for Instagram, 9:16 for Stories and Reels, 16:9 for YouTube, 3:2 and print ratios for paper. Select Custom ratio to type your own width to height numbers.
Read the result. The calculator shows the maximum crop width x height in whole pixels, which side of the photo is the limiting factor, and how many megapixels remain after the crop.
Use the pixel count to judge print size. Divide each dimension by 300 to get the largest tack-sharp print in inches at 300 PPI, or by 240 for very good quality.
The Formula: How the Max Crop Is Found
The math is simple but tedious by hand. The calculator tries fitting the target ratio at the full original width first. If the resulting height fits inside the original height, you have your answer. If it does not fit, the height becomes the limiting side and the width is derived from it. Either way, the result is the biggest possible rectangle at exactly the ratio you want, rounded down to whole pixels so no fractional pixel remains.
A concrete example: 6000 x 4000 at 16:9. Trying full width gives 6000 x 3375, which fits inside 4000, so the max crop is 6000 x 3375, about 20.3 MP. At 1:1 square, full width gives 6000 x 6000, which does not fit, so height limits: 4000 x 4000, or 16 MP. The square crop keeps 80 percent of the long side and loses a third of the pixels, which is the real cost of cropping for Instagram.
Worked Example: Instagram Portrait From a DSLR File
You shot 6000 x 4000 on a full-frame camera and want the best 4:5 portrait crop for Instagram. Select 4:5. Full width attempt: 6000 x 4800 does not fit the 4000-pixel height, so height limits the crop: 5000 x 4000. That keeps 20 MP, plenty for a 1080 x 1350 export and far more than enough for a sharp 8 x 10 print at 300 PPI (which needs only 3000 x 2400).
Now compare a 9:16 Story crop from the same file. Full width gives 6000 x 10667, wildly beyond the height, so height limits again: 2250 x 4000, just 9 MP. That is still fine for a phone screen at 1080 x 1920, but it shows why heavy vertical crops from landscape originals deserve a second look before you print them large.
Practical Tips
Shoot with the crop in mind. If you know the photo will end up 4:5 on Instagram, leave headroom on the sides so the crop does not clip elbows or the top of a building. Many cameras can overlay crop guides or shoot in a cropped aspect mode, which shows you the final frame while recording the full file as a safety net.
For print work, memorize the three common print ratios: 3:2 matches 4x6, 7:5 matches 5x7, and 4:5 matches 8x10. Standard camera files are 3:2, so 5x7 and 8x10 prints always need a trim. Check the crop on screen before ordering prints, because labs center-crop automatically and can slice through faces you wanted to keep.
Frequently Asked Questions
What is the max crop for a 16:9 ratio from a 6000x4000 photo?
The maximum 16:9 crop from a 6000x4000 image is 6000 x 3375 pixels. The width is the limiting side here, because 6000 / 16 x 9 = 3375, which fits inside the 4000-pixel height. This calculator finds the limiting dimension for you and rounds to whole pixels.
What aspect ratio should I use for Instagram posts?
Instagram feed posts look best at 4:5 portrait (1080 x 1350 pixels), which uses the most screen space in the feed. Square 1:1 (1080 x 1080) is the classic safe choice, and landscape posts use 1.91:1. For Instagram Stories and Reels, use 9:16 (1080 x 1920).
Does cropping reduce image quality?
Cropping removes pixels, so the final image has less resolution than the original, but the remaining pixels keep their full quality. A crop that keeps more than about 8 megapixels still prints beautifully at 8x10 inches. The danger is over-cropping: cutting a 24 MP photo down to 2 MP leaves you with a soft, small file.
How do I crop without losing resolution for print?
You cannot crop without losing some pixels, but you can keep the loss minimal by cropping to the largest dimensions that fit your ratio. For print, aim for 240 to 300 pixels per inch at the final print size. A 3000 x 2400 pixel crop (4:5) prints at 10 x 8 inches at 300 PPI, which is plenty sharp.
What is the difference between aspect ratio and resolution?
Aspect ratio is the shape of the image (the proportional relationship between width and height, like 4:3 or 16:9), while resolution is the total number of pixels (like 6000 x 4000). Two images can share the same aspect ratio but have totally different resolutions. Cropping changes both the pixel count and, unless you crop proportionally, the aspect ratio.
Why do my prints come back with parts cut off?
That happens when your photo's aspect ratio does not match the print size. A 3:2 photo printed as a 5x7 (which is 3.5:2.5, or 7:5) must be cropped on the long side. Use this calculator to preview the exact crop for common print sizes like 4x6 (3:2), 5x7 (7:5), and 8x10 (4:5) before you order.