Aspect Ratio Calculator
Calculate image aspect ratios, resize dimensions proportionally, and preview common image and video formats online for free.
Original Dimensions
Resize Proportionally
Enter image dimensions to calculate the ratio.
Aspect Ratio Result
Simplified Ratio
16:9
Decimal Ratio
1.7778
New Dimensions
1280 × 720
Aspect Ratio Preview
16:9
Visual representation of the selected proportions; not an actual image resize.
What is an aspect ratio?
It describes the proportional relationship between image width and height. A 1920 × 1080 image has a 16:9 aspect ratio, commonly used for widescreen video and displays.
How to Calculate Aspect Ratio
Enter the original width and height, or choose a common ratio preset. The calculator simplifies the ratio and shows its decimal value. Enter a new width or height to calculate matching dimensions while preserving the original proportions.
Aspect ratios are useful for photographs, video thumbnails, presentations, website banners, and responsive layouts. This calculator determines the required pixel dimensions; it does not modify or download an image file.