Aspect Ratio Calculator: Frequently Asked Questions

There is no single standard, as modern websites are responsive. Hero images and video embeds typically use 16:9. Feature images often use 3:2 or 16:9. Product images use 1:1 (square). Cards use various ratios. The CSS aspect-ratio property lets you choose any ratio for any element.

They are the same ratio expressed differently. 16:9 = 16 ÷ 9 = 1.777... Aspect ratios can be written as W:H (16:9) or as a single decimal (1.78:1, meaning 1.78 wide for every 1 tall). The calculator shows both forms.

4K UHD width is 3840px. For 16:9: height = width × 9/16 = 3840 × 9 ÷ 16 = 2160px. So 4K UHD is 3840×2160. The calculator does this instantly — enter ratio 16:9 and width 3840.

iPhone screens vary by model. iPhone 14 and 15 are 1170×2532 pixels, which simplifies to approximately 9:19.5 (often rounded to 9:20 in design contexts). Older iPhones (SE, 8) are 750×1334 (≈9:16). For iOS app design, 390×844 points (logical pixels) is the iPhone 14 design canvas.

GCD (Greatest Common Divisor) is used to simplify ratios to their lowest terms. 1920 and 1080 share a GCD of 120, so 1920÷120 = 16 and 1080÷120 = 9, giving the simplified ratio 16:9. 2048 and 1536 share a GCD of 512, giving 4:3.

The classic padding-bottom trick: give the container position: relative and padding-bottom: X% where X = (height/width) × 100. For 16:9: padding-bottom: 56.25%. Place content inside with position: absolute; inset: 0. This works because vertical padding is calculated as a percentage of the element's width.