Calculate Aspect Ratio from Dimensions
Resize While Keeping Aspect Ratio
Convert Between Aspect Ratios
📊 Common Aspect Ratios
📖 How to Use
Calculate Ratio: Enter width and height to find the aspect ratio
Resize: Enter original dimensions and new width OR height to maintain ratio
Convert: Enter a ratio and one dimension to calculate the other
❓ Frequently Asked Questions
What is aspect ratio?
Aspect ratio is the proportional relationship between the width and height of an image, video, or screen. It's expressed as two numbers separated by a colon (e.g., 16:9), where the first number represents width and the second represents height.
What is the most common aspect ratio?
The most common aspect ratio for modern displays and videos is 16:9 (widescreen). It's used by HDTVs, computer monitors, YouTube videos, and most streaming content. The 4:3 ratio was standard for older TVs and is still used in some contexts.
How do I calculate aspect ratio from pixels?
To calculate aspect ratio from pixel dimensions, divide both the width and height by their greatest common divisor (GCD). For example, 1920×1080 pixels: GCD is 120, so 1920÷120=16 and 1080÷120=9, giving you 16:9.
What aspect ratio is best for YouTube?
YouTube recommends 16:9 aspect ratio for standard videos. For YouTube Shorts, use 9:16 (vertical). YouTube will add black bars (letterboxing or pillarboxing) if your video doesn't match these ratios.
What's the difference between 16:9 and 4:3?
16:9 is wider (widescreen), used by modern TVs and monitors. 4:3 is more square-shaped, used by older TVs and some tablets. 16:9 provides more horizontal viewing area, ideal for movies and gaming.
What aspect ratio is 1920x1080?
1920×1080 has an aspect ratio of 16:9. This resolution is commonly known as Full HD (FHD) or 1080p and is the standard for most modern displays and video content.
How do I resize an image without changing aspect ratio?
To resize without changing aspect ratio, only change one dimension (width OR height) and calculate the other proportionally. Use our Resize tool: enter original dimensions and new width, and we'll calculate the corresponding height automatically.
What aspect ratio is best for Instagram?
Instagram supports multiple ratios: 1:1 (square) for feed posts, 4:5 (portrait) for maximum feed visibility, 9:16 for Stories and Reels, and 1.91:1 (landscape) for ads. Square (1:1) and portrait (4:5) posts get the most engagement.
Does aspect ratio affect resolution?
Aspect ratio and resolution are related but different. Resolution is the total number of pixels (e.g., 1920×1080), while aspect ratio is the shape (16:9). Different resolutions can share the same aspect ratio: 1920×1080, 1280×720, and 3840×2160 are all 16:9.
What is 21:9 aspect ratio used for?
21:9 (ultrawide) is used for cinematic movies, ultrawide computer monitors, and immersive gaming. Movies like those in CinemaScope format use this ratio for a more panoramic viewing experience.