Keeping the aspect ratio avoids stretched or squashed images. Common ratios are 16:9 for video, 4:3 for older screens and 1:1 for social posts.
How to use the Aspect Ratio Calculator
- Original width
- Original height
- New width
- Want to work backwards? Type a value into New height and New width is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
The ratio is simplified with the greatest common divisor and the new height is scaled in proportion.
Inputs explained
| Field | What to enter |
|---|---|
| Original width | A number |
| Original height | A number |
| New width | A number |
What each result means
- New height = [New width]×[Original height]÷[Original width]
- Ratio width = [Original width]÷gcd([Original width], [Original height])
- Ratio height = [Original height]÷gcd([Original width], [Original height])
- Decimal ratio = [Original width]÷[Original height]
Example values
How the main result changes when New width changes and everything else stays at the example values above:
| New width | New height |
|---|---|
| 640 | 360 |
| 960 | 540 |
| 1,280 | 720 |
| 1,600 | 900 |
| 1,920 | 1,080 |
| 2,560 | 1,440 |
Formula
New height = new width × original height ÷ original widthWorked example
Inputs — Original width: 1,920; Original height: 1,080; New width: 1,280.
Results — New height = 720; Ratio width = 16; Ratio height = 9; Decimal ratio = 1.7778.
Frequently asked questions
What is 1920 × 1080 as a ratio?
16:9.
Why do some ratios look odd, like 64:27?
That is 21:9 “ultrawide” expressed exactly.
What formula does the Aspect Ratio Calculator use?
New height = new width × original height ÷ original width.
Can I work backwards from the result?
Yes. Type the result you want into New height and the calculator finds the matching new width.