Aspect Ratio Calculator: Resize Width and Height
This aspect ratio calculator works out the width or height you need to resize an image, video or screen without stretching it. Enter the original size or a ratio such as 16:9, type the new width or height, and the other number is filled in. It also turns any resolution into its simple ratio and lists common sizes.
| Common sizes at this ratio |
|---|
Everything runs in your browser. Nothing you enter is sent to or stored on our server.
Quick answer: To keep the same shape, new height = new width × original height ÷ original width. A 1920 × 1080 (16:9) video resized to 1280 pixels wide must be 720 pixels high.
How to use the aspect ratio calculator
- Enter the original width and height in pixels, or tap a ratio such as 16:9 or 4:5.
- Type the new width to get the matching height, or the new height to get the width.
- Read the simplified ratio, the preview shape and a list of common sizes at that ratio.
Common aspect ratios
| Ratio | Used for | Example sizes |
|---|---|---|
| 16:9 | YouTube, TVs, monitors, presentations | 1280 × 720, 1920 × 1080, 3840 × 2160 |
| 9:16 | Stories, Reels, TikTok, Shorts | 1080 × 1920 |
| 4:3 | Older TVs, iPads, many compact cameras | 1024 × 768, 1600 × 1200 |
| 3:2 | DSLR and mirrorless photos, 6 × 4 in prints | 3000 × 2000, 6000 × 4000 |
| 1:1 | Instagram square posts, profile pictures | 1080 × 1080 |
| 4:5 | Instagram portrait posts | 1080 × 1350 |
| 1.91:1 | Link previews on Facebook, LinkedIn and X | 1200 × 630 |
| 21:9 | Ultrawide monitors, cinema | 2560 × 1080, 3440 × 1440 |
What is aspect ratio?
Aspect ratio is the relationship between width and height, written as width:height. It describes shape, not size: 1280 × 720 and 3840 × 2160 are both 16:9. To find a resolution’s ratio, divide both numbers by their greatest common divisor; for 1920 × 1080 that is 120, giving 16:9. Some sizes, such as 1366 × 768, do not simplify neatly and are called “about 16:9”.
Tips for resizing without distortion
- Always change width and height together, keeping the ratio, or the picture will look stretched or squashed.
- To fit a different ratio, crop instead of stretching, or add bars (letterboxing) to fill the space.
- Video sizes work best as even numbers, and many encoders prefer multiples of 8 or 16.
Ready to resize? Use the image resizer. Check your own display with what is my screen resolution, or work with percentages in the percentage calculator.
FAQ
What is the aspect ratio of 1080p?
1920 × 1080 is 16:9.
What size is 16:9 at 1000 pixels wide?
1000 × 562.5, so use 1000 × 563, or choose 1024 × 576 for an exact 16:9 size.
More free tools
See all of them on the QuickOnlineTips free online tools page and play our free online games.