Aspect Ratio Calculator
Simplify an aspect ratio and calculate width or height while preserving proportions.
Preserving proportions
Enter original width and height, then choose the new dimension you know. The other is calculated at the same proportion without uploading an image.
New height = new width × original height ÷ original width
Simplified ratio
The greatest common divisor reduces integer dimensions: 1920 × 1080 becomes 16:9. Presets provide common starting ratios but do not determine image quality.
Frequently asked questions
Does this resize an image file?
No. It calculates dimensions; use Image Resizer to process a file.
Why can results contain decimals?
Some ratios do not produce whole pixels at the selected target.
Does 16:9 always mean 1920 × 1080?
No. Many resolutions share the same ratio.
Explore all online image tools