Aspect Ratio Calculator
Enter any two known values (width, height, or ratio) to instantly calculate the missing dimension and see the simplified ratio.
To keep an image's shape when you resize it, new height = new width × original height ÷ original width.
Use the Aspect Ratio Calculator
Original Dimensions
Common Presets
Scale To
Enter one value — the other is calculated automatically.
Enter width and height to calculate the aspect ratio
Simplified Ratio
Visual Preview
Scaled Dimensions
New Width
—
px
New Height
—
px
Quick answer
To keep an image's shape when you resize it, new height = new width × original height ÷ original width. A 1920 × 1080 image scaled to 1280 wide becomes 1280 × 720, and both are 16:9. Enter your size to get the missing side and the simplified ratio.
Examples
| Resolution | Simplified ratio |
|---|---|
| 1920 × 1080 | 16:9 |
| 3840 × 2160 (4K) | 16:9 |
| 1080 × 1920 | 9:16 |
| 1024 × 768 | 4:3 |
| 6000 × 4000 | 3:2 |
| 1080 × 1350 | 4:5 |
| 2560 × 1080 | 64:27, sold as 21:9 |
| 3440 × 1440 | 43:18, sold as 21:9 |
Enter your width and height.
Summary
The Aspect Ratio Calculator helps you maintain correct proportions when resizing images or designing layouts. Enter your original dimensions and a new width or height, and it instantly calculates the missing value. It also simplifies any ratio to its lowest terms using the greatest common divisor.
How it works
- Enter the original width and height of your image.
- Type a new width or new height in the "Scale" section.
- The calculator fills in the missing dimension to preserve the ratio.
- The simplified ratio (e.g. 16:9) is shown automatically.
- Use the preset buttons for common ratios like 16:9, 4:3, or 1:1.
Use cases
- Resize a photo without distorting it.
- Scale banner or ad creatives to different sizes.
- Find the simplified ratio of any custom resolution.
- Check whether two images share the same aspect ratio.
- Calculate canvas dimensions for video or UI design.
- Convert between common display resolutions proportionally.