Calculators
Aspect Ratio Calculator
Simplify an image ratio and calculate proportional dimensions.
Runs in your browser · No file or text uploads
Preparing your tool…
What Aspect Ratio Calculator helps you do
Find the ratio and pixel count of an image or video frame. Change one dimension and calculate the other while preserving the original proportions.
How to use it
- Enter the current width and height in pixels.
- Choose a new width or height.
- Calculate the ratio, megapixels and new integer dimensions.
Input and output example
INPUT
1920 × 1080 / New width: 1280OUTPUT
16:9 / 1280 × 720 / Original: 2.0736 MP
Supported formats and limits
- Pixel dimensions must be positive safe integers.
- New dimensions are rounded to the nearest pixel, so the final ratio can differ slightly.
How the result is calculated
Ratio = width/gcd(width,height) : height/gcd(width,height). New height = new width × original height ÷ original width. 1 MP = 1,000,000 pixels.
Frequently asked questions
Does this resize the actual file?
No. This tool calculates dimensions. Use Image Resize to change an image file.