Free tool · no login
Aspect ratio calculator for ads (9:16, 4:5, 1:1)
Enter a width and height in pixels to get the aspect ratio, its decimal and the height you need at a target width, such as 1080 pixels.
Aspect ratio
Enter your numbers to see the result.
Free tool by Telehealth Media · telehealthmedia.com
Common ad shapes: 9:16 (full-screen vertical), 4:5 (feed portrait), 1:1 (square). Full list in the ad specs table.
How it works
The aspect ratio is width to height in its simplest form.
- Ratio = width / greatest common divisor : height / greatest common divisor
- Decimal = width / height
- Height at a target width = target width x height / width, rounded
Vertical video for Reels, Stories and TikTok is usually 9:16. Feed posts often use 4:5 or 1:1.
Worked example
A video is 1,080 by 1,920 pixels. A static is 1,200 by 1,500 and needs to be 1,080 wide.
| File | Ratio | Height at 1,080 wide |
|---|---|---|
| 1,080 x 1,920 | 9:16 | 1,920 px |
| 1,200 x 1,500 | 4:5 | 1,350 px |
These numbers illustrate the formula; enter your own.
Telehealth notes
- Keep claims and disclaimers away from the edges of vertical video, where platform buttons cover them.
- Make statics in more than one ratio from the start: resizing late often cuts off text.
Questions
What aspect ratio is 1080 by 1920?
9:16, the full-screen vertical shape used for Reels, Stories and TikTok.
What is the difference between 4:5 and 9:16?
4:5 is a shorter portrait shape used in feeds. 9:16 fills the whole phone screen.
Are my files uploaded?
No. You only type numbers; nothing is uploaded or stored.