Calculate the aspect ratio of any dimensions, scale width or height while keeping the ratio locked. Perfect for images, video, and screen design.
Aspect ratio is the proportional relationship between width and height of a rectangle, expressed as W:H (width:height). For example, 16:9 means for every 16 units of width, there are 9 units of height. Common ratios include 16:9 (widescreen), 4:3 (standard TV), 1:1 (square), and 9:16 (portrait video).
16:9 is the standard widescreen aspect ratio used by most modern displays, including HDTVs, computer monitors, smartphones, and online video platforms. It provides a balanced viewing experience and is the native format for HD video (1920×1080), 4K (3840×2160), and most digital content.
Enter your width and height into the calculator above. The tool finds the greatest common divisor (GCD) and divides both dimensions by it to get the simplified ratio. For example, 1920×1080 has a GCD of 120, so 1920÷120 = 16 and 1080÷120 = 9, giving 16:9.
When you enter a new width or height in the Scale Dimensions section, the calculator automatically computes the other dimension to maintain the aspect ratio. For example, with a 16:9 ratio, entering a width of 1280 will give you a height of 720 (1280 ÷ 16 × 9).
Absolutely! For YouTube, use 16:9 (widescreen). For Instagram stories and TikTok, use 9:16 (portrait). For Instagram square posts, use 1:1. The calculator helps you resize images while keeping the correct proportions for each platform's requirements.
4:3 is the older, boxier aspect ratio used by traditional TVs (640×480, 800×600, 1024×768). 16:9 is the widescreen format used by modern displays. 4:3 is better for older content and some photography, while 16:9 is ideal for movies, TV shows, and web design.