Aspect Ratio Calculator & Resolution Scaler
Calculate proportional pixel dimensions, reduce aspect ratios with GCD algorithms, and preview responsive video canvases.
1. Dimensions & Proportions
Standard Resolution Presets
16 : 9 (Widescreen)
16:9
Simplified2.07 MP
2,073,600 Px1.778
MultiplierLandscape
Horizontalaspect-ratio: 16 / 9;
aspect-video
Responsive Proportional Canvas Box
Scale PreviewClick "Run AI Geometry Audit" to evaluate streaming platform bitrate requirements, responsive UI container CSS, and video export encoding presets. Your data is 100% private to you—zero server access.
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The Pillarbox Blunder: How Letterboxing and Incorrect Video Aspect Ratios Cost Streaming Creators 35% in Engagement
An engineering analysis of vertical video adoption, responsive CSS aspect-ratio properties, and pixel density scaling.
The Vertical Video Revolution (9:16 vs 16:9)
Over 82% of all social media video consumption now occurs on mobile smartphones in portrait mode (9:16). Uploading horizontal 16:9 videos to TikTok or Instagram Reels forces the player to apply pillarbox black borders, reducing viewable screen real estate by over 66% and slashing viewer retention by more than 35%.
Standard Video Resolutions & Aspect Ratio Cheat Sheet
| Standard | Resolution (W x H) | Aspect Ratio | Primary Platform |
|---|---|---|---|
| 4K Ultra HD (UHD) | 3840 x 2160 | 16:9 | YouTube, Netflix, 4K Monitors |
| 1080p Full HD | 1920 x 1080 | 16:9 | Standard Web Video, Twitch |
| Vertical Full HD (Mobile) | 1080 x 1920 | 9:16 | TikTok, Instagram Reels, Shorts |
| Square HD | 1080 x 1080 | 1:1 | Instagram Feed, Facebook Posts |
Frequently Asked Questions (Aspect Ratio & Scaling)
How is an aspect ratio calculated?
An aspect ratio is calculated by dividing both the pixel width and height by their Greatest Common Divisor (GCD). For example, a 1920x1080 resolution has a GCD of 120, simplifying to 16:9.
What are the most common aspect ratios for video and social media?
The most common aspect ratios are 16:9 for YouTube and widescreen TV (1920x1080, 3840x2160), 9:16 for TikTok, Instagram Reels, and YouTube Shorts (1080x1920), 1:1 for Instagram feed posts (1080x1080), and 4:3 for classic photography and iPad displays.
What is the difference between letterboxing and pillarboxing?
Letterboxing adds black bars to the top and bottom of a video when fitting a widescreen image onto a taller display (e.g. 21:9 movie on a 16:9 screen). Pillarboxing adds black bars to the left and right sides when fitting a narrow image onto a wider screen (e.g. 4:3 video on a 16:9 display).