Calculate image and video dimensions while maintaining the correct aspect ratio. Enter dimensions, choose a preset, or pick from common resolutions — all processed instantly in your browser.
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Aspect ratio is the proportional relationship between width and height. It's expressed as two numbers separated by a colon — for example, 16:9 means the width is 16 units for every 9 units of height. Maintaining the correct ratio prevents images from looking stretched or squished.
16:9 is the standard for HD, Full HD, and 4K displays. 4:3 was the classic TV format. 21:9 is used for ultrawide monitors and cinematic content. 1:1 is popular for social media squares, and 9:16 dominates vertical mobile video formats like Stories and Reels.
When resizing images or video, always scale proportionally to avoid distortion. Lock the aspect ratio, change one dimension, and let the calculator compute the other. This ensures your content looks sharp and professional at any size.
An aspect ratio is the proportional relationship between the width and height of an image or video, expressed as two numbers separated by a colon (e.g., 16:9). It matters because maintaining the correct aspect ratio prevents images and videos from appearing stretched or distorted. Common aspect ratios include 16:9 for widescreen displays, 4:3 for traditional monitors, and 1:1 for square social media posts.
To calculate the aspect ratio from given dimensions, find the Greatest Common Divisor (GCD) of the width and height, then divide both values by the GCD. For example, for 1920×1080: GCD(1920, 1080) = 120, so 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, giving an aspect ratio of 16:9. Our calculator does this automatically — just enter your width and height.
Different platforms prefer different ratios. Instagram posts use 1:1 (square) or 4:5 (portrait). Instagram Stories and TikTok use 9:16 (vertical). YouTube and Facebook videos use 16:9 (widescreen). Twitter headers use 3:1. Our tool includes preset buttons and a common resolutions table to quickly find the right dimensions for any platform.
Lock the ratio using the lock toggle, then change either the width or height — the other dimension will auto-calculate. For example, if you have a 16:9 image at 1920×1080 and want it 1280px wide, enter 1280 for width and the height will automatically calculate to 720px, preserving the 16:9 ratio perfectly.
Maintaining the correct aspect ratio is critical in video production. Standard HD video uses 16:9 (1920×1080), while cinematic widescreen uses 21:9. Vertical videos for TikTok and Reels need 9:16. Use our calculator to quickly determine the right resolution for your export format and platform.
Designers need to calculate dimensions for banners, hero images, thumbnails, and social media graphics. Enter your target width and let the calculator compute the height based on your required aspect ratio. Perfect for creating responsive layouts that look great at any breakpoint.
Each social media platform has preferred dimensions. Instagram posts work best at 1080×1080 (1:1) or 1080×1350 (4:5). Instagram Stories need 1080×1920 (9:16). YouTube thumbnails are 1280×720 (16:9). Use the resolutions table below to find the exact size for every platform.
Different monitors use different aspect ratios. Standard widescreen monitors are 16:9, ultrawide monitors are 21:9, and older displays use 4:3. When creating wallpapers, presentations, or digital signage, knowing the exact pixel dimensions for your target display is essential.
Standard photo prints use a 3:2 aspect ratio (matching 35mm film), while 4:3 is common for many digital cameras. When preparing images for print at specific sizes (4×6, 5×7, 8×10), use the calculator to verify dimensions match before cropping or resizing.
Game developers must support multiple screen resolutions while maintaining visual consistency. From 720p to 4K, all common resolutions share the 16:9 ratio. Our calculator helps determine sprite sizes, UI element dimensions, and texture resolutions that scale correctly across devices.
The aspect ratio of an image or video is calculated by finding the Greatest Common Divisor (GCD) of its width and height, then dividing both dimensions by that number. For example, a 1920×1080 image: GCD(1920, 1080) = 120, giving 16:9. This simplified ratio tells you the proportional relationship between width and height, regardless of the actual pixel count.