Image Aspect Ratio Calculator
Calculate the ratio from image width/height and find a ratio-preserving size.
Category: Image Tools
When to use?
Use it to match sizes without breaking the ratio when resizing, to check aspect ratios in design/video work, or to compute thumbnail/banner specs by ratio.
How to use
- Enter the image width and height in pixels.
- The simplest ratio and decimal ratio are calculated.
- Enter a target width to get the ratio-preserving height.
Input Explanation
Enter the image width and height in pixels. Common ratios like 16:9 and 4:3 can be filled with preset buttons.
Calculation Basis
It divides width and height by their GCD for the simplest integer ratio, and width ÷ height for the decimal ratio. Resizing uses target width × (height ÷ width) for the new height.
Usage Examples
- Ratio-preserving resize - Compute a size that does not break the ratio when shrinking or enlarging.
- Check aspect ratio - Check whether an image or video ratio is 16:9 or 4:3.
- Thumbnail/banner specs - Compute thumbnail/banner sizes to a fixed ratio.
Examples
- 1920 × 1080 → 16 : 9 (decimal ratio 1.7778)
- Ratio-preserving resize: 1920×1080 to target width 1280 → 1280 × 720
Cautions
- Enter accurate values including decimals for a precise ratio.
- It is a calculator for ratios; it does not need an image file.
Guides
Resize without breaking the ratio
Multiply the target width by (original height ÷ original width) for a ratio-preserving height. This prevents distortion when enlarging or shrinking.
The simplest ratio
Divide width and height by their GCD for an integer ratio like 16:9 or 4:3. You can also check the decimal ratio (width ÷ height).
FAQ
How is the simplest ratio found?
It divides width and height by their greatest common divisor for the smallest integer ratio.
How is the ratio-preserving size calculated?
Multiply the target width by (original height ÷ original width) for the new height.
What is the decimal ratio?
Width divided by height; 1.7778 corresponds to 16:9.
Do I need to upload an image file?
No. Just enter the width and height pixel numbers.
Related Tools
- Image Resizer - Resize multiple images in the browser with aspect ratio kept, no server upload.
- PPI Calculator - Calculate pixel density (PPI) and dot pitch from screen diagonal size and resolution.
- Image Cropper - Enter pixel coordinates to crop just the area you need, in the browser.
- Screen Size Compare - Compare display sizes by diagonal, aspect ratio, width, height, and screen area.
- Ratio Calculator - Simplify the ratio of two values, or solve for the unknown in a proportion.
- Image Rotate / Flip - Rotate images in 90-degree steps or flip them horizontally/vertically.