Aspect Ratio Calculator
Calculate aspect ratios, resize pixel dimensions without distortion, and preview scaled widescreen and vertical video canvas sizes.
aspect-ratio: 16 / 9;How Aspect Ratios Prevent Distortion & Letterboxing
Cropping or resizing images and video clips without maintaining their intrinsic aspect ratio causes stretching, squishing, or unsightly black letterboxing bars. Understanding aspect ratios ensures your visual creative assets render sharply across phones, tablets, and desktop displays.
Popular Aspect Ratio Reference
- 16:9: 1920×1080 (FHD), 2560×1440 (2K QHD), 3840×2160 (4K UHD)
- 9:16: 1080×1920 (TikTok, Reels, YouTube Shorts, Stories)
- 4:3: 1024×768, 1440×1080 (Classic television and iPad tablets)
- 1:1: 1080×1080, 2048×2048 (Square Instagram feed photos)
- 21:9: 2560×1080, 3440×1440 (Cinematic film and ultrawide desktop monitors)
Creative & Production Applications
- ✓Vertical Video for TikTok, Reels & Shorts
Scale vertical 9:16 canvas resolutions (1080×1920, 720×1280) for viral social mobile video publishing.
- ✓YouTube & Widescreen 16:9 Video Production
Resize 4K (3840×2160) and 1080p video footage to standard lower bitrates without introducing black letterboxing bars.
- ✓Responsive Web Design & CSS `aspect-ratio`
Generate modern CSS `aspect-ratio: 16 / 9;` declarations for responsive image containers and video iframe wrappers.
- ✓Photography & Print Aspect Ratios (3:2, 4:5)
Ensure digital camera RAW photos match standard photographic paper printing dimensions (8×10, 4×6 inches).
Why Use This Aspect Ratio Tool
Bidirectional Dimension Scaling
Input any custom Width to calculate matching proportional Height, or change Height to find Width.
Standard Social & Video Presets
Includes one-tap shortcuts for 16:9 (Widescreen), 9:16 (Stories/Reels), 4:3 (Legacy), 1:1 (Instagram), and 21:9 (Cinematic Ultrawide).
Live Scaled Preview Box
Interactive visual stage dynamically resizes to display the true physical proportions of your ratio.
Instant CSS Code Export
Copy valid CSS `aspect-ratio` syntax for rapid web development in Tailwind or vanilla styles.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio is the proportional relationship between the width and height of an image, video, or display screen. It is written as two numbers separated by a colon (e.g. 16:9), meaning for every 16 units of width, there are 9 corresponding units of height.
What is the aspect ratio of 1920×1080?
1920×1080 is a 16:9 aspect ratio. Dividing both 1920 and 1080 by their greatest common divisor (120) reduces the numbers to 16 and 9.
What is the best aspect ratio for social media videos?
For vertical mobile feeds like TikTok, Instagram Reels, and YouTube Shorts, the standard is 9:16 (1080×1920 px). For standard YouTube, Vimeo, and desktop presentations, 16:9 (1920×1080 px) is standard. For Instagram feed posts, 1:1 (1080×1080 px) or 4:5 portrait (1080×1350 px) are ideal.
How do I use the CSS aspect-ratio property?
Modern CSS provides the native `aspect-ratio` property. Instead of using the old 'padding-top hack', you can write `aspect-ratio: 16 / 9;` on any HTML element, and the browser will automatically maintain proportions during responsive container resizing.
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