Aspect Ratio Calculator
Free aspect ratio calculator to find ratios, resize images proportionally, and convert between 16:9, 4:3, 21:9, 1:1 and custom ratios. Perfect for video, photography & displays.
Enter Image or Video Dimensions
Common Aspect Ratios Reference
| Ratio | Decimal | Common Use | Examples |
|---|---|---|---|
| 1:1 | 1.00 | Social media posts, profile pictures | Instagram feed, CD covers, app icons |
| 4:3 | 1.33 | Classic TV, presentations, tablets | iPad, PowerPoint, old TV shows |
| 3:2 | 1.50 | Photography, print | DSLR cameras, 35mm film, 4×6 prints |
| 16:10 | 1.60 | Laptops, computer displays | MacBook Pro, business monitors |
| 16:9 | 1.78 | HD video, modern TV, streaming | YouTube, HDTV, Netflix, monitors |
| 1.85:1 | 1.85 | Cinema flat/theatrical | Most theatrical releases |
| 2:1 | 2.00 | Univisium, mobile displays | Netflix originals, modern smartphones |
| 21:9 | 2.33 | Ultrawide monitors, gaming | LG UltraWide, gaming monitors |
| 2.35:1 | 2.35 | CinemaScope widescreen | Star Wars, epic films |
| 2.39:1 | 2.39 | Anamorphic widescreen | Modern blockbusters, IMAX |
| 9:16 | 0.56 | Vertical video, mobile | TikTok, Instagram Reels, Shorts |
| 4:5 | 0.80 | Portrait photos | Instagram portrait, Pinterest pins |
16:9 Resolution Chart
The 16:9 aspect ratio is the most common format for TVs, monitors, and video content. Here are standard resolutions:
4:3 Resolution Chart
The 4:3 aspect ratio was the standard for older TVs and monitors. It's still used for tablets and presentations:
How to Calculate Aspect Ratio
What is Aspect Ratio?
Aspect ratio is the proportional relationship between an image's width and height. It's expressed as two numbers separated by a colon (like 16:9) or as a decimal (like 1.78). The aspect ratio doesn't describe actual size—it describes the shape.
The Formula
To calculate aspect ratio from dimensions:
Aspect Ratio = Width ÷ GCD(Width, Height) : Height ÷ GCD(Width, Height)Where GCD is the Greatest Common Divisor
Example Calculation
For a 1920 × 1080 image:
• GCD(1920, 1080) = 120
• Width ratio = 1920 ÷ 120 = 16
• Height ratio = 1080 ÷ 120 = 9
• Aspect ratio = 16:9
Calculating Missing Dimension
To find a missing dimension while maintaining ratio:
New Height = (Known Width × Ratio Height) ÷ Ratio WidthNew Width = (Known Height × Ratio Width) ÷ Ratio HeightWhen to Use an Aspect Ratio Calculator
Video Production
Export videos for YouTube (16:9), TikTok (9:16), or cinema (2.35:1)
Photography
Crop photos for print (3:2) or Instagram (1:1, 4:5)
Web Design
Create responsive images that scale without distortion
Social Media
Optimize content for each platform's preferred dimensions
Gaming
Set up ultrawide monitors (21:9) or multi-monitor displays
TV & Displays
Calculate viewing dimensions for different screen sizes
Frequently Asked Questions
What is the most common aspect ratio for video?
16:9 is the most common aspect ratio for video content. It's the standard for HDTV, YouTube, streaming services, and most computer monitors. It replaced the older 4:3 format around 2010.
What aspect ratio is 1920x1080?
1920x1080 (Full HD or 1080p) has a 16:9 aspect ratio. This resolution is the most common for monitors, TVs, and video content. The simplified ratio is calculated by dividing both numbers by their GCD (120).
What's the difference between 16:9 and 16:10?
16:10 is slightly taller than 16:9. It was popular for computer monitors and laptops (like MacBooks) because it provides more vertical space for documents and web browsing. 16:9 is better for watching videos.
What aspect ratio should I use for Instagram?
Instagram supports multiple ratios: 1:1 (square, 1080×1080), 4:5 (portrait, 1080×1350), 1.91:1 (landscape, 1080×566), and 9:16 (Stories/Reels, 1080×1920). Portrait 4:5 typically performs best for feed posts.
Why do movies have black bars on my TV?
Black bars (letterboxing) appear when a film's aspect ratio doesn't match your TV's 16:9 ratio. Most theatrical films use wider ratios like 2.35:1 or 2.39:1 to create a more cinematic feel, resulting in horizontal black bars.
How do I resize an image without distortion?
To resize without distortion, maintain the original aspect ratio. Use this calculator to find the matching dimension—enter your target width or height and the original ratio to get the proportional measurement.
What is 21:9 ultrawide aspect ratio used for?
21:9 (2.33:1) is used for ultrawide monitors popular with gamers and professionals. It provides more horizontal screen space for immersive gaming, video editing timelines, and viewing multiple windows side by side.
What aspect ratio is TikTok and YouTube Shorts?
TikTok, YouTube Shorts, and Instagram Reels all use 9:16 vertical video format. The recommended resolution is 1080×1920 pixels. This is essentially 16:9 rotated 90 degrees for mobile-first viewing.
Related Calculators
Understanding Aspect Ratios: A Complete Guide
The History of Aspect Ratios
The first films in the late 1800s used a nearly square 1.33:1 (4:3) aspect ratio, which became the Academy ratio. When television adopted this same format, Hollywood responded by developing wider formats like CinemaScope (2.35:1) to differentiate the theatrical experience.
The 16:9 ratio emerged as a compromise in the 1980s, chosen because it's the geometric mean between 4:3 and 2.35:1—making it suitable for displaying both TV content and films with minimal letterboxing.
Aspect Ratios for Different Platforms
YouTube: Recommends 16:9 (1920×1080 or 3840×2160). Videos in other ratios will have black bars or pillarboxing.
Instagram: Supports 1:1 (feed optimized), 4:5 (portrait, maximum feed visibility), 1.91:1 (landscape), and 9:16 (Stories/Reels).
Twitter/X: Supports up to 1:3 and 3:1 ratios. 16:9 and 1:1 perform well.
Facebook: Recommends 1:1 for feed posts, 9:16 for Stories, and 16:9 for video ads.
Choosing the Right Aspect Ratio
Your choice of aspect ratio should consider your platform, content type, and viewing context. For maximum reach, create master content in 16:9 and crop or adapt for other platforms. For mobile-first content, start with 9:16 vertical video.
This calculator provides accurate aspect ratio calculations for digital media. Results may need rounding for pixel-perfect dimensions in some applications.