Aspect Ratio Calculator
Type a width and a height to get the aspect ratio, or a ratio and one side to get the other. Any unit works: pixels, inches or centimeters.
The aspect ratio of 1920×1080 is
16:9
1.78:1, landscape. Widescreen: HD and 4K video (1920×1080, 3840×2160), most monitors and TVs.
Common sizes with this shape
- 1200×675
- 1280×720
- 1600×900
- 1920×1080
- 2560×1440
- 3840×2160
Checking an image for Pinterest? The Pinterest image size checker reads a picture's size for you and crops it to 2:3.
Quick answer: an aspect ratio is a picture's width compared with its height. To find it, divide both numbers by the largest number that goes into both: 1920×1080 ÷ 120 = 16:9. To find a missing side, multiply the side you know by the other half of the ratio and divide by its own half: at 16:9, a width of 1280 needs a height of 1280 × 9 ÷ 16 = 720. A Pinterest pin is 2:3, for example 1000×1500.
How to use it
- The ratio of a size: type the width and the height. You get the ratio by the name people use, the same ratio as one number to one (1.78:1), and whether it is landscape, portrait or square. You also get common sizes with the same shape.
- The missing side: type a ratio (16:9, 2:3, 1.91:1 all work) or tap a common one, choose whether you know the width or the height, and type it. The other side appears, rounded to a whole number, and the page says so when rounding was needed.
The numbers can be in any unit. A ratio has no unit, so 1920×1080 pixels and 16×9 inches have the same shape.
Common aspect ratios and what uses them
| Ratio | As one number | What uses it |
|---|---|---|
| 1:1 | 1:1 | Square: Pinterest carousels and collections, most profile pictures |
| 2:3 | 1:1.5 | Portrait: Pinterest's recommended pin (1000×1500); 4×6 in prints held upright |
| 3:2 | 1.5:1 | Landscape: many camera photos (35 mm film and most DSLRs) and 6×4 in prints |
| 4:5 | 1:1.25 | Portrait: 8×10 in prints; one of Pinterest's recommended video shapes |
| 3:4 | 1:1.33 | Portrait: phone photos taken upright, at most phones' default setting |
| 4:3 | 1.33:1 | Landscape: phone photos at most phones' default setting, older TVs and many tablets |
| 9:16 | 1:1.78 | Vertical video and phone screens: Pinterest idea ads (1080×1920) |
| 16:9 | 1.78:1 | Widescreen: HD and 4K video (1920×1080, 3840×2160), most monitors and TVs |
| 16:10 | 1.6:1 | Many laptop screens and monitors (1440×900, 1920×1200) |
| 5:7 | 1:1.4 | Portrait: 5×7 in prints |
| 1:2 | 1:2 | Very tall: the tallest a Pinterest video may be |
| 1.91:1 | 1.91:1 | Wide: the widest a Pinterest video may be |
| 21:9 | 2.33:1 | Ultrawide monitors and cinema |
The Pinterest shapes are quoted from Pinterest's own product specs, checked 26 September 2026. The rest are the standard sizes of video, screens and photo prints.
Working it out by hand
- 1920×1080. The largest number that divides both is 120: 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, so it is 16:9.
- 1366×768, a common laptop screen, divides down only to 683:384. That is 1.7786:1, within 0.05% of 16:9 (1.7778:1), so everybody calls it 16:9, and so does this calculator. It shows the exact ratio too.
- 1440×900 divides down to 8:5, which is the same shape as 16:10, the name screens are sold under.
- A 4:5 portrait 1080 wide is 1080 × 5 ÷ 4 = 1350 tall.
- A 1.91:1 image 1200 wide is 1200 ÷ 1.91 = 628.27 tall, so 628 in whole pixels. The ratio is a rounded number itself, which is why the result is not whole.
Mistakes that change the answer
- Width first. 16:9 is wide and 9:16 is tall. They are the same numbers with a different shape, and a video or a pin made the wrong way round is cropped or bordered.
- Ratio is not resolution. 1280×720 and 3840×2160 are both 16:9. The ratio is the shape, and the resolution is how many pixels fill it.
- 16:10 is not 16:9. Many laptops are 16:10. A 16:9 video on them shows thin bars, and a 16:10 wallpaper on a 16:9 screen is cropped.
- Resizing one side only stretches the picture. Change both sides by the same factor, or use the missing-side mode to get the other one.