Aspect Ratio Calculator
Find the ratio of any size and scale dimensions while keeping proportions
- Files never leave your device
- Runs in your browser
- Free, no sign-up, no watermark
Dimensions
px
px
Reduced ratio
16:9
Landscape · 2.1 MP
Decimal
1.778:1
1:0.563
Nearest common ratio
16:9
exact match
Resize with locked ratio
Type a new width or height; the other side follows the ratio.
:
px
px
Video encoders usually need even sizes; some codecs prefer multiples of 8 or 16.
1,280 × 720
Scale to fit
Fit the dimensions above inside a box (contain), or fill the box and crop (cover).
px
px
Fit inside (contain)
1,080 × 607.5
Scale 56.3%
Fill and crop (cover)
1,920 × 1,080
Scale 100% · Crops 840 × 0
How to use Aspect Ratio Calculator
Find the aspect ratio of any width and height, match it to the nearest common ratio such as 16:9 or 21:9, and work out new sizes that keep the ratio. It also shows how a size fits inside or fills a box, with presets for video, social media and print.
- 1
Enter the Width and Height in pixels, or click one of the Common sizes.
- 2
Read the Reduced ratio, the Decimal value and the Nearest common ratio, along with orientation and megapixels.
- 3
Under Resize with locked ratio, type a New width or New height and choose Round to: Any, Even, × 8 or × 16.
- 4
Under Scale to fit, enter a Box width and Box height to compare Fit inside (contain) with Fill and crop (cover).
Frequently asked questions
Does it resize my image file?
No. It only calculates dimensions. To change an actual image, use the Image Resizer with the numbers you get here.
Why round to even numbers or multiples of 8 or 16?
Video encoders usually need even dimensions, and some codecs work best with multiples of 8 or 16. Round to does this for the resize results.
Why is 2560×1080 not exactly 21:9?
It reduces to 64:27; “21:9” is the marketing name for ultrawide screens. The tool shows the exact ratio, the nearest named ratio and how far off it is.
Can I enter ratios with decimals, like 1.85:1?
Yes. Decimal values are reduced exactly, so 1.85 : 1 becomes 37:20.
What is the difference between contain and cover?
Contain scales the size to fit entirely inside the box, leaving empty bars. Cover scales it to fill the box and shows how many pixels get cropped.