Aspect ratio is the proportional relationship between width and height, expressed as W:H. Common ratios: 16:9 (widescreen HD video, monitors), 4:3 (old TV and photos), 1:1 (Instagram square), 9:16 (vertical/mobile video), 3:2 (35mm camera photos), 21:9 (ultrawide monitors). To maintain aspect ratio when resizing: new height = (original height / original width) x new width.
📂 Developer Tools
📻 Aspect Ratio Calculator
Calculate aspect ratios, resize images while maintaining proportions, and find equivalent dimensions. Essential for designers, photographers, and video creators.
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✅ Trusted Tool
The 365tool.net Aspect Ratio Calculator uses standard ratio mathematics. Free for designers, video creators, photographers, and developers. No sign-up needed.
🤔 How Does This Work?
The Aspect Ratio Calculator uses ratio mathematics:
Find ratio: calculate GCD of width and height, divide both by GCD
Find dimension: (known dimension / known ratio part) x unknown ratio part
Convert: maintain one dimension, calculate other from new ratio
❓ Frequently Asked Questions
What is 16:9 aspect ratio?▼
16:9 is the standard widescreen aspect ratio for HD and 4K video, computer monitors, and televisions since the early 2000s. For every 16 units of width, there are 9 units of height. Common 16:9 resolutions: 1280x720 (720p), 1920x1080 (1080p/Full HD), 2560x1440 (1440p/QHD), 3840x2160 (4K/UHD).
How do I maintain aspect ratio when resizing?▼
Multiply or divide both dimensions by the same factor. Or use the formula: New Height = (Original Height / Original Width) x New Width. Example: resize 1920x1080 to 1280 wide. New height = (1080/1920) x 1280 = 720. So 1280x720 maintains the 16:9 ratio. Our calculator does this automatically.
What aspect ratio should I use for social media?▼
Facebook and YouTube videos: 16:9. Instagram posts: 1:1 (square) or 4:5 (portrait for more feed space). Instagram Stories and TikTok: 9:16. Twitter/X images: 16:9. LinkedIn: 1.91:1 or 1:1. Profile pictures: 1:1. Thumbnails: 16:9. Always check current platform specifications as they update frequently.
What is a safe zone for video?▼
The safe zone is the area of a video frame guaranteed to be visible on all displays. Action safe zone: inner 90% of the frame. Title safe zone: inner 80%. Some old TVs and displays crop the edges. Modern displays usually show 100% of the frame, but staying within safe zones prevents elements from being cut off on some devices.
What is pixel aspect ratio?▼
Pixel aspect ratio (PAR) describes the shape of individual pixels. Most modern displays use square pixels (1:1 PAR). Some older video formats used non-square pixels — standard definition TV used rectangular pixels (0.9 or 1.2 PAR). This meant 720x480 video appeared wider than expected on modern square-pixel displays. This is rarely relevant today.
16:9 is the standard widescreen aspect ratio for HD and 4K video, computer monitors, and televisions since the early 2000s. For every 16 units of width, there are 9 units of height. Common 16:9 resolutions: 1280x720 (720p), 1920x1080 (1080p/Full HD), 2560x1440 (1440p/QHD), 3840x2160 (4K/UHD).
How do I maintain aspect ratio when resizing?▼
Multiply or divide both dimensions by the same factor. Or use the formula: New Height = (Original Height / Original Width) x New Width. Example: resize 1920x1080 to 1280 wide. New height = (1080/1920) x 1280 = 720. So 1280x720 maintains the 16:9 ratio. Our calculator does this automatically.
What aspect ratio should I use for social media?▼
Facebook and YouTube videos: 16:9. Instagram posts: 1:1 (square) or 4:5 (portrait for more feed space). Instagram Stories and TikTok: 9:16. Twitter/X images: 16:9. LinkedIn: 1.91:1 or 1:1. Profile pictures: 1:1. Thumbnails: 16:9. Always check current platform specifications as they update frequently.
What is a safe zone for video?▼
The safe zone is the area of a video frame guaranteed to be visible on all displays. Action safe zone: inner 90% of the frame. Title safe zone: inner 80%. Some old TVs and displays crop the edges. Modern displays usually show 100% of the frame, but staying within safe zones prevents elements from being cut off on some devices.
What is pixel aspect ratio?▼
Pixel aspect ratio (PAR) describes the shape of individual pixels. Most modern displays use square pixels (1:1 PAR). Some older video formats used non-square pixels — standard definition TV used rectangular pixels (0.9 or 1.2 PAR). This meant 720x480 video appeared wider than expected on modern square-pixel displays. This is rarely relevant today.