Aspect Ratio Calculator
DesignCalculate aspect ratios and resize dimensions while maintaining proportions. Essential for responsive images.
Calculate Ratio
New Dimensions
Calculate new height/width while maintaining the 16:9 aspect ratio.
What is This Tool?
An aspect ratio calculator computes dimensions, scales images, and converts between common aspect ratios. Enter width and height to find the ratio, or lock a ratio and calculate the missing dimension — essential for responsive design, video production, and image resizing.
Common aspect ratios include 16:9 (widescreen video/monitors), 4:3 (traditional TV/iPad), 1:1 (square/Instagram), 21:9 (ultrawide), and 3:2 (DSLR photos). Understanding aspect ratios ensures content displays correctly across different screen sizes and platforms without unwanted cropping or letterboxing.
Common Use Cases
Responsive Web Design
Calculate image dimensions for responsive breakpoints, ensuring correct aspect ratios across mobile, tablet, and desktop.
Video Production
Convert between video aspect ratios (16:9, 4:3, 21:9, 9:16) and calculate resolution dimensions for different platforms.
Social Media Assets
Size images for Instagram (1:1, 4:5, 9:16), YouTube thumbnails (16:9), Twitter cards (2:1), and Facebook posts (1.91:1).
Print Design
Calculate dimensions for print materials, photo prints, and posters while maintaining correct proportions.
Frequently Asked Questions
What is an aspect ratio?
The proportional relationship between width and height, expressed as W:H. A 16:9 ratio means for every 16 units of width, there are 9 units of height.
How do I maintain aspect ratio when resizing?
Lock the ratio and change one dimension — the other calculates automatically. In CSS, use aspect-ratio: 16/9 or the padding-bottom percentage trick.
What aspect ratio is 1920x1080?
16:9 (1920÷120=16, 1080÷120=9). This is the standard Full HD and widescreen aspect ratio.