Calculate dimensions, find aspect ratios, and resize images or videos while maintaining proportions. Perfect for designers, videographers, and web developers.
Last updated: April 2026 | By Patchworkr Team
Aspect ratio is the proportional relationship between width and height, expressed as two numbers separated by a colon (e.g., 16:9). It describes the shape of a rectangle, not its absolute size.
A 16:9 aspect ratio means for every 16 units of width, there are 9 units of height. Both a 1920×1080 screen and a 3840×2160 screen have the same 16:9 aspect ratio—they're the same shape, just different sizes.
Know what you're calculating: Do you have width and need height? Do you have both and need the ratio? Are you resizing? Why: Different scenarios require different formulas. Identifying your goal first prevents confusion.
Write down the dimension(s) you know. If finding a missing dimension, you'll also need the aspect ratio (e.g., 16:9). Why: Organized inputs prevent calculation errors and ensure you use the correct formula.
Why: Each scenario has a specific formula. Using the wrong one gives incorrect results.
Plugging your values into the formula. For ratio calculations, find the Greatest Common Divisor (GCD) of both dimensions to simplify the ratio to its smallest form. Why: Simplified ratios (16:9 instead of 1920:1080) are easier to communicate and standardize across devices.
Sanity check your answer. If resizing, verify the ratio is preserved. If finding a dimension, ensure it's reasonable given your input ratio. Why: A quick verification catches typos or formula mistakes before they cause problems in production.
YouTube Thumbnail Resize
Your new image will be 1280 pixels wide and 720 pixels tall, maintaining the original 16:9 widescreen ratio. This smaller version is perfect for web previews, social media, or lower-bandwidth scenarios. Without proper aspect ratio calculation, a naive resize could stretch or squash the image, damaging the visual quality.
16:9 is the standard widescreen format for HD video, TV, and most computer monitors. For every 16 units wide, it's 9 units tall.
Multiply or divide both dimensions by the same factor. Or use the formula: new height = new width × (original height / original width).
16:9 is widescreen (modern TVs, YouTube). 4:3 is more square (old TVs, standard definition video). 16:9 is wider.
Yes, but you'll either crop it (lose top/bottom), stretch it (distortion), or add black bars (pillarboxing). True conversion requires re-shooting.
Instagram feed posts are 1:1 (square), Stories are 9:16 (vertical), and landscape posts are 1.91:1 (nearly 2:1).
Divide both width and height by their GCD. Example: 1920×1080 → GCD is 120 → 16:9.
16:9 is universal. 21:9 (ultrawide) is cinematic but has compatibility issues on some platforms. Stick with 16:9 for most uses.
No. Aspect ratio is shape, not quality. A 1280×720 and 1920×1080 image can both be 16:9, but 1920×1080 has higher resolution.
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