Calculate aspect ratios from dimensions, scale images proportionally, or find dimensions from a ratio. Perfect for web design, video production, and.
An aspect ratio is the proportional relationship between an image or screen width and height, expressed as two numbers separated by a colon (e.g., 16:9). It describes the shape of the frame without specifying actual pixel dimensions.
16:9 (widescreen) is the most common aspect ratio for modern videos, monitors, and TVs. It is the standard for YouTube, HD television, and most video content.
Use the "Scale Dimensions" mode. Enter your original dimensions and provide either the new width or new height. The tool will calculate the missing dimension to preserve the exact aspect ratio.
Instagram supports multiple ratios: 1:1 (square), 4:5 (portrait), and 1.91:1 (landscape). The 4:5 portrait ratio is recommended as it takes up the most screen space in the feed.
The Greatest Common Divisor (GCD) is the largest number that divides both width and height evenly. Dividing both dimensions by the GCD gives the simplest ratio. For example, 1920×1080: GCD(1920,1080) = 120, so 1920/120 : 1080/120 = 16:9.
All processing runs entirely in your browser using verified algorithms. Results are computed with full double-precision — no server-side rounding or data transmission occurs.