Aspect Ratio Calculator
Work out the aspect ratio of any width and height, resize a picture or video while locking its ratio, or pick a preset like 16:9, 4:3 or 21:9. Also solves any proportion A:B = C:D and simplifies ratios — with decimals, megapixels and orientation. Free and instant.
About Aspect Ratio Calculator
This aspect ratio calculator does three related jobs. In aspect mode, it finds the ratio of any width and height and resizes images or video frames while keeping that ratio locked — pick a preset like 16:9, 4:3 or 21:9, enter one new dimension and it solves the other. It also reports the decimal ratio, megapixels, orientation and scale factor.
The other two modes handle general ratio math: solve any proportion A:B = C:D by cross-multiplication (fill three values, leave one blank), or simplify a ratio to its lowest terms using the greatest common divisor.
It is a staple for resizing photos without distortion, sizing video embeds and thumbnails, scaling recipes or plans, and checking print and screen dimensions — free and instant.
How to use Aspect Ratio Calculator
- Pick a mode: aspect ratio, solve proportion, or simplify ratio.
- In aspect mode, set the width and height or choose a common preset such as 16:9.
- Enter your new pixel size, leaving one field blank — the tool locks it to the same ratio.
- For proportions, fill three of the four values; the solver finds the missing one.
- Read the simplified ratio, decimal value, resolved size, megapixels and orientation.