Case 1
- Width in pixels
- 1920px
- Height in pixels
- 1080px
1.7778
Open with these valuesAspect Ratio Calculator
1.7778:1
Result: 1.7778 :1The aspect ratio is width divided by height: 1920 × 1080 gives 1.7778, the decimal behind 16:9. The whole-number form comes from dividing both sides by their greatest common divisor — 120 in that case. Not every resolution reduces neatly: 1366 × 768 is 1.7786, close to 16:9 but not equal to it.
Worked examples
Case 2
- Width in pixels
- 1280px
- Height in pixels
- 1024px
1.2500
Open with these valuesCase 3
- Width in pixels
- 2560px
- Height in pixels
- 1080px
2.3704
Open with these valuesHow it's calculated
ratio = width ÷ height
- StepEnter the width and the height in pixels.
- StepRead the decimal ratio: 1.7778 is 16:9, 1.3333 is 4:3, 1 is square.
- ResultFor the whole-number form, divide both sides by their greatest common divisor.
Reference table
| Width, height (px) | Reduced ratio | Decimal |
|---|---|---|
| 1000, 1000 | 1:1 | 1.0000 |
| 1280, 1024 | 5:4 | 1.2500 |
| 1024, 768 | 4:3 | 1.3333 |
| 1920, 1080 | 16:9 | 1.7778 |
| 1366, 768 | 683:384 | 1.7786 |
| 2560, 1080 | 64:27 | 2.3704 |
Questions
How do I calculate an aspect ratio?
Divide the width by the height for the decimal form. For the whole-number form, divide both by their greatest common divisor: 1920 and 1080 share 120, which leaves 16:9.
What does 16:9 mean?
Sixteen units of width for every nine of height, the standard for HD and 4K television, most laptops and online video. As a decimal it is 1.7778, so the picture is noticeably wider than it is tall.
Why does 1366 × 768 not come out as 16:9?
Because it genuinely is not. Its greatest common divisor is only 2, leaving 683:384, and the decimal is 1.7786 rather than 1.7778. Screens sold as 16:9 at that resolution are a fraction of a percent off.
What are the common aspect ratios?
16:9 for modern screens and video, 4:3 for older monitors and many tablets, 16:10 for some laptops, 21:9 for ultrawide, and 1:1 for square social posts.
Does cropping or resizing change the ratio?
Cropping does, because it removes pixels from one side only. Scaling both sides by the same factor does not — 1920 × 1080 and 1280 × 720 are both 1.7778.
Sources and last check
Information, not professional advice.