Aspect Ratio Calculator
Calculate dimensions for any aspect ratio instantly. Enter a width or height and get the matching dimension. Perfect for video, photography, and design.
Quick Presets
Common Screen Resolutions & Aspect Ratios
Standard Displays
| Name | Width | Height | Ratio |
|---|---|---|---|
| HD (720p) | 1280 | 720 | 16:9 |
| Full HD (1080p) | 1920 | 1080 | 16:9 |
| QHD (1440p) | 2560 | 1440 | 16:9 |
| 4K UHD | 3840 | 2160 | 16:9 |
| 8K UHD | 7680 | 4320 | 16:9 |
Social Media
| Name | Width | Height | Ratio |
|---|---|---|---|
| Instagram Post | 1080 | 1080 | 1:1 |
| Instagram Story / Reel | 1080 | 1920 | 9:16 |
| YouTube Thumbnail | 1280 | 720 | 16:9 |
| TikTok Video | 1080 | 1920 | 9:16 |
| Facebook Cover | 820 | 312 | ~2.6:1 |
| X / Twitter Post | 1200 | 675 | 16:9 |
| LinkedIn Banner | 1584 | 396 | 4:1 |
Apple Devices
| Name | Width | Height | Ratio |
|---|---|---|---|
| iPhone 15 Pro | 1179 | 2556 | ~9:19.5 |
| iPad Pro 12.9" | 2048 | 2732 | 3:4 |
| MacBook Pro 16" | 3456 | 2234 | ~16:10 |
| iMac 27" | 5120 | 2880 | 16:9 |
Cinema & Film
| Name | Width | Height | Ratio |
|---|---|---|---|
| Academy (1.375:1) | 2048 | 1490 | 1.375:1 |
| Flat (1.85:1) | 3996 | 2160 | 1.85:1 |
| Scope (2.39:1) | 4096 | 1716 | 2.39:1 |
| IMAX (1.43:1) | 5616 | 3924 | 1.43:1 |
| DCI 4K | 4096 | 2160 | ~1.9:1 |
What Is an Aspect Ratio?
An aspect ratio is the proportional relationship between the width and height of an image, screen, or video frame. Written as two numbers separated by a colon (like 16:9 or 4:3), it describes the shape of a rectangle without specifying its actual size. The first number represents the width, and the second represents the height.
Aspect ratios are fundamental in video production, photography, web design, and display technology. Choosing the right ratio ensures your content looks correct across different devices and platforms, preventing unwanted cropping, stretching, or black bars.
How to Calculate Aspect Ratios
To find the aspect ratio of a given width and height, divide both numbers by their greatest common divisor (GCD). For example, a 1920 x 1080 display: the GCD of 1920 and 1080 is 120. Dividing both by 120 gives 16 and 9 — so the aspect ratio is 16:9.
To calculate a missing dimension when you know one dimension and the desired ratio: if you have a width of 1920 and want a 16:9 ratio, multiply the width by the height portion of the ratio and divide by the width portion: 1920 × 9 ÷ 16 = 1080.
Why Aspect Ratios Matter for Video and Photography
Different platforms and mediums require specific aspect ratios. YouTube videos use 16:9, Instagram posts work best at 1:1 or 4:5, and Stories and Reels need 9:16. Using the wrong aspect ratio means your content will be cropped or letterboxed, losing visual impact and professionalism.
In cinema, the aspect ratio is a creative choice. Wide formats like 2.39:1 (CinemaScope) create an epic, panoramic feel, while narrower ratios like 1.33:1 (Academy) feel more intimate. Directors like Christopher Nolan and Wes Anderson are known for their deliberate use of specific aspect ratios to enhance storytelling.
Common Aspect Ratios Explained
The standard for HD and 4K video, modern monitors, and TVs. Used by YouTube, Netflix, and most streaming platforms.
The classic TV and computer monitor format. Still used by iPads and some presentation slides.
A perfect square. Popular for social media posts, album art, and profile pictures.
Vertical video for mobile-first content. Used by TikTok, Instagram Stories/Reels, and YouTube Shorts.
Ultrawide format for cinematic content and ultrawide monitors. Provides an immersive viewing experience.
Traditional 35mm film and DSLR photo format. Used by many digital cameras and some laptops.
Who Uses an Aspect Ratio Calculator?
Video Editors
Calculate the exact dimensions for any delivery format. Whether you're exporting for YouTube (16:9), Instagram Reels (9:16), or cinema (2.39:1), get pixel-perfect dimensions instantly.
Photographers
Resize and crop images while maintaining the correct aspect ratio. Perfect for preparing photos for print (3:2, 5:4) or social media (1:1, 4:5) without distortion.
UI/UX Designers
Design responsive layouts for different screen sizes and devices. Quickly calculate dimensions for hero images, cards, thumbnails, and responsive containers.
Social Media Managers
Create platform-optimized visuals. Each social network has specific dimension requirements — get them right every time for maximum engagement and visual impact.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio is the proportional relationship between the width and height of an image, screen, or video. It is expressed as two numbers separated by a colon, such as 16:9 or 4:3. The first number represents the width and the second represents the height.
What aspect ratio is 1920x1080?
1920x1080 has an aspect ratio of 16:9. This is the standard Full HD (1080p) resolution used in most modern monitors, TVs, and video content.
How do I calculate aspect ratio from dimensions?
To calculate the aspect ratio from width and height, find the greatest common divisor (GCD) of both numbers and divide each by it. For example, for 1920x1080: GCD is 120, so 1920/120 = 16 and 1080/120 = 9, giving you 16:9.
What is the best aspect ratio for YouTube videos?
The standard aspect ratio for YouTube videos is 16:9. YouTube's player is designed for 16:9, so videos at 1920x1080 (Full HD) or 3840x2160 (4K) will display perfectly without black bars.
What aspect ratio should I use for Instagram?
Instagram supports multiple aspect ratios: 1:1 (square) for feed posts, 4:5 (portrait) for maximum feed visibility, and 9:16 (vertical) for Stories and Reels. Landscape posts use 1.91:1.
What is the difference between 16:9 and 4:3?
16:9 is a widescreen format used in modern HD/4K displays and video. 4:3 is the older, more square format used in classic TVs and some tablets like the iPad. 16:9 is wider, making it better for cinematic content, while 4:3 works well for documents and presentations.
How do I resize an image without changing the aspect ratio?
To resize while maintaining the aspect ratio, change one dimension (width or height) and calculate the other using the ratio. For example, to resize a 16:9 image to 1280px wide: height = 1280 × (9/16) = 720px. Our calculator does this math instantly.
What aspect ratio is used in cinema?
Cinema uses several aspect ratios: 1.85:1 (Flat) is common for dramas and comedies, 2.39:1 (Scope/CinemaScope) is used for epic and action films, and 1.43:1 is used for IMAX. The choice of ratio affects the visual storytelling style.
Can I use a custom aspect ratio?
Yes! Our calculator supports custom aspect ratios. Simply enter any two numbers as your width and height ratio (e.g., 7:3 or 2.35:1) and the calculator will compute the matching dimensions for any width or height you provide.
What is the aspect ratio for ultrawide monitors?
Most ultrawide monitors use a 21:9 aspect ratio (2560x1080 or 3440x1440). Super ultrawide monitors use 32:9 (5120x1440), which is essentially two 16:9 displays side by side.